Is human fertility declining? What is the cause and what can we do about it. Our guest is Dr. Shanna Swan, an award-winning scientist based at Mount Sinai Medical Center and one of the world’s leading environmental and reproductive epidemiologists. She is the author of Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race.
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Welcome, everyone to creating a family talk about infertility. I'm Dawn Davenport, your host and the director of creating a family.org. In addition to this podcast, we are a nonprofit that brings unbiased medically accurate information to you. So welcome check us out at our website as well creating a family.org. Today we're going to be talking about is human fertility declining and if so, what we can do, we'll be talking with Dr. Shanna Swan. She is an award winning scientist based at Mount Sinai Medical Center and one of the world's leading environmental and reproductive epidemiologist. She is the author of countdown, how our modern world is threatening sperm counts, altering male and female reproductive development, and imperiling the future of the human race.
What a title. Welcome, Dr. Swan to creating a family. We are so happy to talk with you about this. absolutely fascinating book. First of all, thanks for writing it. Thanks for the years of research that went into the writing of it. Thanks for having me, Don. And by the way, feel free to call me Shawna. It's fine. Okay. I just wanna hear. Okay, great. I will do just that. Yeah. Okay. Let me ask a question. I mean, that's kind of the basic, the thing that began, all of this is sperm count. In human males declining, we'll start at the beginning of the most basic, which kind of the research is to did that kind of kicked all of this off.
I've been tracking this question for about 30 years.
I started when a Danish study looked at sperm count worldwide, and concluded it had declined significantly, actually 50% in 50 years. And that was a very big study, it was published in 1992. And I was skeptical.
I appreciated that you included your skepticism in the book, because as a natural born skeptic, myself, I thought, okay, I would be skeptical to write. But it was important, it was clearly important. And so I decided to spend actually turned out to be six months, looking into this question. And seeing what I tried to do was make the trend go away? Because that's what we do. We say, well, well, maybe this will explain or maybe this is what some of those factors were like, Okay, well, maybe now man are using, they're using methods in labs that count in a different way, in such a way that, you know, on average is lower.
And we also asked, Well, maybe the men are different. That's right, you know, so maybe the men today who give a semen sample are going to be more concerned more, you know, they're going to be having lower sperm counts, compared to the past. That was studies were done on on, on men who were concerned about their sperm count, therefore, they would be more likely to have a reduced sperm count. Right, exactly. So that was a concern. And and then, you know, other things like we know, smoking affects sperm, how could that be a factor, age of the man, obesity of the man? So
I had raised these questions, and so had many scientists around the world. So I kind of collected all of the suggested causes. And I did analysis, I got all the 61 studies. And I considered all these factors and adjusted for them statistically.
And assumed before I ran the numbers that this would kind of flatten the curve, but it did not. That was big shock, actually, in fact, it did nothing. It did not change the slope at all. Not to the, you know, first decimal place. So, so Wow. So then I thought, Hmm, maybe this is real. And then that changed my life, actually, because then I started in a whole new direction of research, right. And so that was 1992. I published my analysis 97, published a second analysis in 2000. and kept looking at this. And then in about 2014, a colleague and I met at a conference and he said, you know, that old study from 1992, we should update that. And so we made plans to do that. And that's what we did. With the paper that we published in 2017. It was different in many ways. It was different because we used what was then modern methods of doing this kind of a summary analysis. There's called meta analysis method.
We used that. And we were much more rigorous. And we laid out ahead of time what our protocol was going to be and what our inclusion criteria were going to be. And because we now we were aware of all the pitfalls that we could have fallen into, turned out to be a very, very big job. And it took me to bring on seven people. Because there were, you know, just like 43,000 studies that we had to go through by search after we search the literature. So, so we took the time to do that, because we thought it was important enough.
And then we published it. And what we published in 2017,
became kind of a driving force for the book. So what did we say in 2017? Yeah, in 2017, we said, but when we did the systematic meta analysis, on the whole world's published literature in English, by the way, we didn't have the ability to translate, you know, foreign language studies. But most countries use English as a scientific language. So when we considered all that we saw that there had been, as had been reported, and in 1992, a drop of about 50%, in sperm concentration, a little more in total account, in the almost 40 years of our follow up. So after all that work, and all that time, I came up with a conclusion which supported the 1992 paper. But it also supported, if you will, a whole new set of research and attention to this problem, because this paper being so well done, was the most highly cited paper in that journal for that year. And in all,
literature, it ranked 27th in the world. So it was extremely highly cited and respected. And that gives me and other people a lot of concern. And, and the book, I'll just show you, because I haven't have it here. Here's the book.
This was that came out of that. When an agent read that paper for literary agent, she came to me and she said, Would you write a book about this? Right? And I was reluctant to actually again,
because I've given hundreds of talks, and I've
published hundreds and hundreds of papers. And it just didn't seem that I needed to do this also. But she convinced me that this would be a different audience. And it would be in a different voice. If I got a writer to write with me, and I did. And her name is Stacy colino. And we're co authors on this. And she, Stacy is wonderful. And she's very, very good at talking in a way that people can hear in a way that scientists sometimes cannot. So that's how countdown got written and why gotten written? That's a long answer to your question.
But let me ask a question. Now, if the decline that you found and the meta analysis that you published in 2017, is it worldwide? Or is it just in developed countries? That's a great question. So we did not search for developed countries. In fact, it's hard to give a metric for what that is. But what we did was we took all comers that met our criteria, the criteria had nothing to do with economic status, or race, ethnicity, geography, anything, we just took everything. But then when we examined them to see where publications came from, and when they were published, it turned out that Western countries for want of a better word, which we included North America, Europe, Australia, and New Zealand, those countries had data over the whole time period.
But other countries, such as Africa, Asia,
Middle East, had very few studies, but they tended to be all at the end of the study period. So you couldn't do a retrospective comparison, but you can see where they stood now. Right. Okay. And we have to separate these if we wanted to, because if we put them all together, and we saw a decline, it might be because those other countries coming in late in the study period. We're pulling the curve down. You see that? Yeah, sure. So So we said we did fit separate models for Western countries and other countries, and here's what
We learned, the significant decline that I told you about is in western countries, the other countries, it's not that they don't have a decline, it's that there are too few to make any statistical conclusions. And with a weight, the way that shows up, if you're a statistician, you you put some confidence bands around your number. And if that number isn't, is that band is too wide, if you will, basically says you don't have enough information to me. And that's what happened. So we now are seeking further data to update that. But we don't know the.
So it but we do know that other countries are now publishing many more studies of this kind. And so we hope to get an answer about that. And very excited to get an answer about that maybe in the coming year. So is sperm count the only measure of sperm health that's declining? Are we also seeing a change in sperm motility or morphology also?
Well, probably they are all declining. How ever I say that only because I know they're correlated. Now, the reason we couldn't, we actually tried to get data initially on morphology and motility. But the problem is that we required
that the studies included use the same analytic methods, in other words, counted the same way, using who standards did motility in the same way it did morphology in the same way. And over the course of this time period, those methods have changed quite a bit. And so we couldn't get enough data using a single method to be able to say anything about those trends. So I would just say, based on the correlations among these things, you know, men who have low sperm count tend to have problems in these other areas. But it's not definitive at all, we don't have those data at this point.
So we, we know that I'm thinking of things that are easy to measure. And we know that testosterone levels can impact sperm, both sperm count, as well as other aspects of male health. That so and that's a relatively easy thing to I would assume to measure. So do have you do any of the reports or in your research indicate that there's been a change in the average testosterone level in men worldwide, or in developed countries? Yes, most of the data are from again, developed countries. And the and the studies on testosterone trends is different. So our study, we didn't publish a trend, we published a meta analysis. But there are several studies that published within the country, how testosterone has trended. And those studies show a decline at about the same rate, which is about 1% per year. So the decline that we reported was 40 years a decline of 52%, just over 1% per year. testosterone is also declining about 1% per year. And by the way, so are some female endpoints also getting worse at about 1% per year, as is total fertility. So we have this, if you will, this picture of decline, males and females many parameters at about the same rate. Interesting. We're going to switch here in just a moment to talking about women's women's reproductive health as well. But before we leave the discussion about sperm count, do we know the reason now, I mean, we know that testosterone is dropping, and we know sperm count is dropping, and that testosterone might be influencing the sperm count drop, but what's causing the drop in sperm count? Our system? Yeah, I mean, you can imagine that that is a $4 million question. Yeah. Yeah. Yeah, yeah. So here's how I answer that. And we, of course, spent a lot of time in countdown discussing this. So first, I take the very big picture, and I say, what causes biological change? What possibly could cause biological effects? So first cut, if you will, is to say, Well, there are genetic influences. And there are environmental influences. Those are they if you have that those two categories, you kind of cover the whole picture. So if you look first to genetic, we believe that this is not the explanation because we're looking at changes in about two generations or less. And major shifts do not occur is too fast for evolution that, you know, we don't know any examples that go that fast. So even though genes might interact with environment
And different genetic backgrounds might change the effect of environmental influences. Genes alone are not going to explain this. Okay. So then you have environment. So environment also is a very big category, huge category is everything else. Right, exactly. And so I like to break it down into
non chemical factors and chemical factors. Okay. So among the non chemical factors, the ones that we know of that can influence the reproductive function and steam quality in particular, their lifestyle factors, the things we do, and we have some control over, for example, smoking, that has an adverse effect on all kinds of reproductive function as it does on our health in general. Stress actually has a measurable we showed in our study, that men who reported two or more stressful life events had significantly lower sperm counts, and is human is stress. Is the modern world. Is it more stressful than than it was 50 years ago? 40 years ago?
definitely is more stressful. And that may be a contributing factor. Absolutely. Absolutely.
And there's no way to control for that in these studies. So that's something other than environment that could be driving this. There is there are the metabolic factors and the things related to exercise, obesity, how has that changed? Are those risk factors for horsepower? Yes, yes. Body weight is actually pretty important. If you are obese you men and women have poor reproductive function. And also if you are very low, or very, you know, you're underweight you, particularly if you over exercise, you know, women have the syndrome, you know, from overexercising weather, don't men straight right. And men also can have decreased function if they over exercise. So it's there's a sweet spot. It's not a straight line. It's not like more as worse, we're the whole range. But there's the good level of exercise, and then there's too much into it, right? And then there's alcohol. So severe, all binge drinking is known to lower sperm count. And we have there's much less on recreational drugs. But the evidence is that more than occasional use of recreational drugs is also linked to lower reproductive function. But remember, there's much less, there's much less research that we don't we can't prove that we know what research does show is that that recreational drug use, especially if done in excess, will decrease real sperm count. Got it? Yeah. And then there's diet. So diet is actually pretty important. And I worked with a group at Harvard, a nutritional group, that this study might come up later. So let me just say what we did was we we recruited young man and Rochester students,
we paid them to fill out a questionnaire and they did other things such as giving us a semen sample and so on, and we can talk about that. But in that questionnaire, they used a standard very well established food frequency questionnaire developed by Harvard
and so we asked them what they ate in the past 24 hours and what they usually eat. And then we published I think, eight papers about the importance of different kinds of foods for semen quality, so they really do matter and I won't go into them all but something called the Mediterranean diet, which you know, we know all know about which is you know, fresh fruit and vegetables, less red meat, less fat, you know, and dairy and so on that Mediterranean diet is actually associated with better sperm count. And then there are other things like you know, processed meats are not great for your sperm count, and actually organic inorganic so eating vegetables that are not organic, actually, you know, showed a lower sperm count. So you know, you can look at those papers, but um, by and large, it's the messages that diet matters. bodyweight matter, it all matters right and
so the way you live your life matters and by the way, couch potato behavior lowers your sperm count also, so so those are the lifestyle factors. And then there are factors which we don't discuss which are things like heat and although he does actually known to decrease sperm count, but he sound radiation and a lot of other non lifestyle things.
Other than chemicals, but my work has been focused on chemicals. Gotcha. And we're gonna we're going to talk about that at the end because it applies to both male and females. Yeah, actually all of these things apply apply to both. Exactly. Yes. Yeah. Yes.
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Is there any just out of curiosity, because I am, I don't think we've done a huge amount of research into this. But the we are all surrounded by Wi Fi. We're surrounded people keep their phones in their pockets, men in particular, is there any indication that our technology and the ubiquitousness of it if that's a word, it would impacts it is particularly if it is close to the gonads and men, you know, we have laptops and not just the heat, we've often talked about the heat of a laptop on your lap. But I'm talking about the the actual, for lack of better word, the raise the the the Bluetooth, the Wi Fi, the the internet in general.
So I, I know there is literature on this. And a long time ago, I studied EMF electromagnetic fields in relation to miscarries. That was in another life when I was studying miscarriage. And we look pretty hard. And we didn't see anything interesting. That's not to say that doesn't affect men. But what I'm saying is the research that I personally have done, which is what I am most comfortable talking about sure has not examined this. And I can't give it a clean bill, bill of health. But I also can't say service, I think for that you'd have to bring on another expert.
Alright, that's fine. All right. Now let's move and talk about women now. Do you see a similar impact on women's reproductive health? And if so, it occurs to me, how do we know with men? You know, we can look at the ejaculate we can look at. And we can count sperm and we can look at sperm. For women, our reproductive tracks are not as easy to quickly examine and look at. And so anyway, so first of all, has there been a decline? in it? Have you seen an impact? And second, how would you know?
So you got it. Right, john, I mean, really is the case that men's reproductive health is just much easier to measure. And it's easier to look at also, because science for a long time has been focused on male inputs, you know, there's been much more if you look at, like heart disease, and all kinds of you know, it's been focused on the male. So there's a lot of reasons that females have been kind of left behind in this discussion, but one of them definitely is that it's harder to look. But I will tell you that just in the last month, a study was published out of Sweden, which did a brilliant in my mind thing, which what they what they did was they looked at women undergoing c section.
So they had access to the organs. And they got tissue, I believe it was uterine tissue, and they looked for levels of persistent organic pollutants in the tissue. And they found that several were elevated in relation to the number of eggs that the woman had in her ovaries. So the
account Yeah, so the egg count is really hard. For most women, we can't look inside you with the way we could for these c section women. But and you can use an ultrasound. But that's actually, first of all, it's expensive. It's not routinely done, and you know, we have to have access to it. And it doesn't tell you much. It tells you something but not much about the quality. So when you get a sperm, you get a semen sample, you can learn a huge amount, right? How do they move? You know what you can look at their chromosomal structure, you know, are there abnormalities, you can look at the shape, you know how many heads and tails and it's too thin and you bet lots and lots of things in addition to their account. But on an ultrasound, you get an egg count. You can also see something about the quality of the eggs, but it's much more limited. So I think for this reason, we you know, we have much less inflammation. There are studies that look at premature ovarian failure, showing that that is increasing and
Definitely, we can look at miscarriage rate. So miscarriage rates are rising, we do not have the same kind of information we have for sperm count. Like, you know, 43,000 men in our meta analysis studied for 40 years, nothing like that we don't have that kind of a major study on miscarriage. But local studies in local countries in shorter time periods show increases in miscarriage rates. Let me let me ask a question about that. We are now able to test for the very earliest times of pregnancy, we can, you know, basically within a couple of weeks of conception, we can test and find out so we know about miscarriages that we wouldn't have known about in the past. So is that I'm sure you've taken that into consideration that you are the studies that you're referring to? Have they taken that into consideration?
So john, I did a study of early pregnancy loss. And let me tell you, it's not for everybody, it is extremely difficult to carry out. Okay, let me just tell you what we had to do. We had to find this was in Kaiser, so we had a population, you know, we had to find First of all, women at risk of pregnancy, right? So because you don't want women in there who are, you know, using oral contraceptives. And if you're looking for, okay, you have to have women at risk of pregnancy, that have to be married, they have to be living with their partner, their partner has to not be traveling. So that was our definition of at risk of pregnancy, we found about 500 of these women who were willing to talk to us and collect a urine sample every day for up to six months, right there. You're making it really hard for people, okay, then you have to have somebody working with the study who will go from house to house to pick up these samples that the woman have to keep in their freezers. Right there, you're making it very difficult. Okay, then you have to take those samples. And we're talking about every sample every day for six months for 500. Women Think about that. You have to measure lots of hormones in those samples, particularly HCG, which is a marker of early pregnancy. We did that. We did that study. There haven't been very many. We did it. There was one Danish study, there was one study by Alan Wilcox at an IHS that probably the first and most important of them. And what we all showed in these studies that the rate of subclinical loss before the woman knows she's pregnant, but we can see it a chemical pregnancy, loss of those pregnancies is arguably around 30% 33% 28%. There, it's very high. It's very high. But there's no way that those studies could be included in any big analysis. Because they're one they're one offs. You can't do lots of studies. You just don't have the Yeah. Yeah. Too expensive. And and, and too and too intrusive in many ways. Right? Right. Expensive, if nothing else, yeah. Okay. So have you seen a decline in the, I guess another way to, to potentially look at female reproductive health would be looking at the fertility rate. And so what does that show? And that's a confusing one, it seems to me, because so many factors, including birth control, if nothing else are postponement of, you know, delay of childbearing? are, you know, moving to from an agrarian society where numbers of children are higher numbers of children are valued? So there's so many factors that can influence it? And, and thank goodness, we have the ability now to control our birth through birth control the number of children we have, but anyway, what what does what is what do we see from a fertility rate? And is that even a good measure? Because of all the things I just mentioned as, as could also influence? So all those points are good. I think it's important to point out that fertility is really complicated. It's easier to talk about infertility, isn't it? But fertility, as it's defined by demographers is simply the number of children born to a woman or a couple. That's the definition. That's the demographic. And the opposite of that, as you point out is not infertility, which implies the inability to conceive, because in the middle there, there's the whole option of not wanting to or
there was the there's the question of choice and, and so the question of how sperm count, or ovarian reserve or any of those biological factors relate to fertility is really, really complicated. However, putting that aside for a minute, your There's wonderful data worldwide data from the World Bank
and if you
Look at that you can google World Bank fertility data, anybody can do that you can see how the fertility rate has decreased overall for the world, which is that it's gone down by 50% or 1% per year, just like sperm count 1% per year from 1960. To the present. So that's, you know, it's gone from five children, per couple, a woman to 2.4, just about the same rate of sperm count has gone down, that is worldwide, that's not Western countries. And surprisingly, just parents statically if you look in there at specific countries, which the same website can allows you to do, you see that, for example, South Africa has declined 60% compared to say, Denmark, or, you know, EU countries, which have declined, maybe 30%. So, actually, the declines contrary to maybe what people think the declines in fertility are greater in underdeveloped countries. Okay. But they're all declining. And like you said, there's many, many reasons for this, and very good reasons, including the availability of contraception, voluntary delaying childbearing, and so on and so forth. Education of women, when there's good research, right? education, women have more opportunities other than motherhood that often have fewer children. Yeah, actually, the urbanization of areas is related to this going down. So So yes, all of those things. And for your listeners who might be interested in this question, which I think is a fascinating and extremely important question. There is a book called empty planet. And it's by Darrell Bricker, and a co author. And, and we talked to Darryl for the book. And, and basically, what they show is that, yes, we have a lot of people in the world now. And that number is going to increase for a while, but probably not for long the projection is, and then it's going to decline, and it will continue to decline, and it will not come back up. Because once a society reduces the number of children born, and once women enter the workforce, and take control over their lives to control the number of children, they will no not go back to having 5678 children. So it's not something that's likely to turn around.
I'd like to say one more thing about that. Sure. And that's to point out that we should be aware that the things that affect our fertility are also affecting the fertility, other than choice are affecting the fertility of non human species. Ah, and
there's a huge literature showing the decline in multiple species. And we hear about this all the time. And these species have smaller litters have actually have smaller genitals, many of them, they have malformed genitals, they have all kinds of problems interfering with their reproduction. But what they don't do is choose to have smaller families. Yeah, it's not a but that's a good way to to tease out the the impact of choice because they're not making a choice. Thank you very much. Thank you. I'm glad you appreciate that. Because I mean, it's absolutely critical. We're not alone on this planet. And true. We know when these animals are examined, they have body burden similar to ours. And they have effects on their reproductive system similar to ours, and they're having smaller families. So it is undoubtedly true that the chemicals in the environment are also on top of these other factors we're looking at have affected family size and fertility. Interesting. It seems to me as I'm thinking about it, that they're going back to female fertility, and how we can measure this. It sounds like fertility rate alone, is it released for human women is not a particularly good measure. So I mean, that's one thing. But what about age of puberty? We certainly hear and, and, and countdown talks about really strong research that shows that girls are entering puberty at a younger age, again in developed countries. So is that a measure of reproductive health in women and could that be impacting potentially fertility?
Definitely, it could be I don't think there have been any studies or other areas to to know the impact of early puberty on say lifetime fertility.
You're gonna have to follow these girls for a very long time. Sure. Right. And we haven't had this data on early puberty very long. And by the way, I'm not sure it is just developed countries, I think it may be as in sperm count, we don't have data from underdeveloped countries or less developed countries. So I have no confidence that this is something that's limited to developed countries. But we can have to go where the data are ranking. So exactly, um, yeah. And there's also a slight extension of reproductive life in the other direction, that women are entering menopause slightly later, as well. So over all, the reproductive lifespan is longer. But whether the impact of that on lifetime fertility is not known. And by the way down, when you say women's fertility, I think what you're talking about is really women's fecund ability, ability to produce a child. Yes. Because, like I said, fertility is a slippery question. It's, you know, it's like the end product, it's measured by the end product. But that's not what I think we all think about when we think about good point. Yeah, so we're talking about this is the definite, what is the likelihood that that a woman who is not contraceptive with a man, having intercourse with a man who is not contraceptive will conceive a child? That's true, that's exactly you know, and you can, you can make a very even more specific, you know, per cycle. And, and as that number of cycles till conception, you know, goes up, then the accountability goes down. And eventually, if it's 12, or more, then they're classified as infertile.
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And the book countdown, you had a chapter that I thought was absolutely fascinating. And it was talking about the increase in gender fluidity for lack of a better term, because that would be more inclusive. And my first thought when when I started on that chapter was thinking, well, that we would expect that because societal acceptance as and so whereas in the past, people would have hidden their gender identity, if because of fear of repercussions, fear of ridicule, or whatever. And now there is less of that. So I would expect that, but you do a good job of of teasing that out and saying, it's more than just that, can you give us a kind of a thumbnail view on how gender fluidity may be being changed as well. And we will then go back to talking as the reasons why but but first of all, let's talk about gender fluidity and how that is impacted. How that is being impacted? Sure. So first of all, let me say, we don't say and I don't believe I would not say that gender fluidity has increased, because we don't really know like you said in the past, it wasn't okay to talk about it. So we really don't have baseline information. And and when, you know, just like you want sperm count today to be compared in similar methods to sperm count 40 years ago, we can ask people today, but we didn't ask them for two years ago. So we don't have any baseline information on gender fluidity. Okay, so that question is an open question, whether there's more whether it is talked about more, absolutely. Whether it's in the social media more, absolutely. But whether there actually is more in the sense that more people believe that they have been assigned the wrong biological sex, they that they want to transition to the opposite sex. That's not No. Okay. There wasn't the opportunity to go to a physician to talk about this. There wasn't insurance support for this, and so on and so forth. There was no you know, no history here. So, okay, so that's the first thing. The second thing I just want to separate because they get conflated. A couple of conditions. One is what's called disorders of sexual development, or ambiguous genitalia or things like that, where there's a physical
change in the genitalia from what would be
For example, in frogs, there are animals that are, can be created with ovaries and testes in the same animal. That's definitely an disorder of sexual development. And there are infants, as you know, we have historical data on infants for a long time that were born with ambiguous genitalia, and so on. So the fact that that can be created in the laboratory or in wild by environmental chemicals suggests that that is a possible contribution. We don't have data saying, here's a population of kids with ambiguous genitalia, and here's their parental exposures that cause that. No, we don't know that. But it is possible, right? It's possible even if if enough animal species do this, Okay, the next level is not about the physical genitalia, but it's about partner choice. So homosexuality, sexual orientation. Yeah, sexual orientation is a little bit vague, because some people conflate that actually with gender identity, but let's just say specifically, homosexuality, so men who prefer to have sex with men only with men or possibly bisexuality. And same thing with women. So that can be created also in the laboratory, and it's seen in wildlife. So frogs are exposed to the chemical Atrazine, the pesticide, males will prefer to mate with males and females. Well, that's, that's more dramatic. And but I think also females with female. So, you know, that's also possibly related to chemicals. However, there are also genetic components. So I would say, for that area, I would say it's possibly related to environmental chemicals. But we, we haven't shown that we've come to the third level, which is where you started, which is gender identity, and that's in your head, isn't it? That's how you feel you should have been born or the or the gender you want to assume. And for that, we can't get information from animals. And the reason is, we can't ask animals.
What, how would they prefer to be male or female? Obviously, we can't ask them. We have a little bit of evidence from animals in some frogs, that seemed to prefer when they made to always be on the bottom or always be on the top, maybe they're telling us something about their preference. But aside from that, very, if you want incidental piece of possible evidence, we don't have any information about chemicals, endocrine disruptors, and we haven't talked about endocrine disruptors, but just let me put it in here. The chemicals I'm most concerned about are those that can influence our body's hormones, and occurrence or hormones. So endocrine disrupters just drop your body's hormones. Okay. So and those are chemicals, which I'm sure we'll talk about where they're found, but they're found in our daily lives. And, and so those chemicals are the best candidates for if anything was linked to gender dysphoria would be those. But I would say, We are a long way from knowing whether that's happening or not. And I would also say that, that you clearly and certainly we are clearly not pathologizing in any way, sexual identity or sexual orientation. Yeah, that was just identifying that what the research is showing one way or the other. All right, well, that now you have brought us to the the kind of the heart of the book, and certainly the heart in many ways of your research, and that is exposure. At the beginning, you talked about how we can rule out genetics because of the help rapid the changes have been. So we're in the environment and of the environment, you talked about two, two avenues, one being two avenues to look at one being non chemical and the other being chemical, and of the non chemical, you're really kind of focusing on some of the lifestyle issues, smoking, stress, obesity, things like that diet. So now we're moving into the other section, which is the chemical. So again, the $64 million question and where are you going to spend a large portion of your life researching is can exposure to environmental toxins impact the can they impact our reproductive health in both males and females? Yes, and so it's, I would maybe slightly word and say, Can environmental chemicals mobility to alter the body's hormones? That is endocrine disruptors impact our body's reproductive health, and and the answer is, Yes, definitely. But maybe should we start and talk a little bit about what these chemicals are? We Yeah, exactly. Yeah. So let's do let's talk about what what the chemicals are and how and what how they work. Exactly. How, how do they disrupt our endocrine system? Yeah.
So the biggest class, the class that I'm most concerned about is the class called salads. And that's pH, gh L, at Bs, which is a big mouthful and unfortunate. But that's their about it. And this class of chemicals, has members that have different purposes. So there are a number of those that are plasticizers, they're put into plastic, to actually make it soft, soft and squishy. So you can think about salads, when you see a rubber duck, or you see a plastic shower curtain, or you see a tube, you know, soft tubing. And turns out that these salads, while they're in the plastic, they're not very tightly bound to it. And so anything going through, or going passing by or in contact with that soft plastic, can absorb some of the salads. And a great example of that is in the nikkyo, when it can be shown that the number of tubes carrying food and other nutrients to the newborn infant in the bassinet. That number of tubes, which are all made of soft plastic and contain validates is directly related to measured levels of salads in the baby's urine, you know, collected, right at the same time, there was a direct passage, if you will, out of the tube, into the food into the baby into the urine because they're water soluble, and then measure the wall. Mm hmm. So once you see that possibility, you can see a lot of other possibilities. You can see other possibilities in a hospital setting, right? For example, for dialysis, blood transfusions all kinds of ways that Alex can get into the body. And you can see it in terms of food processing. So whenever foods come into contact with these salads in soft, you know, soft plastic or possibly plastic linings, they are plastic containers, they can absorb new salads. And I think the biggest takeaway for people is don't ever microwave in plastic because you know, confounding things you have something which is off plastic, and even if it says microwave safe, but yeah, amen. You know, and then it gets into your food. Art also fell lights also found in certain cosmetics and haircare and skincare products. Yeah, thank you, john. That's a whole like other class of uses and, and a different set of values. Because there are like, at least 15, there's more than being found all the time being manufacturer all the time, by the way. And so yeah, so one of the things that validates do is they increase absorption. So that could be absorption, for example of a pesticide into the plant. So they're added to pesticides. I just mentioned that because absorption has many forms. And it can also be absorption of eye cream into our skin.
And of course we want that to happen. And you know, probably good to put that in there to increase absorption but bad because then it's in our skin. They also hold scent. And every fragrance product that we examined. We asked women about their use of fragrance products, whether it was a perfume or it was in laundry soap, and whether it's an air freshener, they all convey satellites into the air which we then breathe, we get these in by the way through our skin you can imagine because you're rubbing on the cream through our ingestion when we eat these foods. And through breathing and dust. They're also retains color. So they're in nail polish. They're in lipstick, they're also in hairspray. So they're all over our personal care products. And yeah, we're getting a big hit of these all the time. And so that's just one class and I haven't even begun to cover it and then there are other classes. So I don't want to go into great detail but just say this phenol way people have heard about BPA in baby bottles in water bottles. That is kind of the opposite of Sally's because the this females make plastic hard. But they also are endocrine active. So going back to the salads, the thing we're most concerned about is that they have the ability to lower the body's testosterone and they
When this happens in the womb,
there's many, many serious consequences for the reproductive development of the boys that are exposed. And that's what a lot of my research has been focused on. But the they also have effects in, in adults, and they can affect. For example, in our study, we found that higher levels of phalloides were associated with less sexual satisfaction in women, because women also have testosterone, if you're going to knock that down is lower than men, of course, but if you need it, and if you lock that down, you can affect sexual function in males, Bisphenol A has been shown to be related to at high doses, particularly in an occupational settings related to male sexual performance and erectile dysfunction, which, by the way, is increasing. Also, if we haven't talked about them, we talked about the trends. So um, that's two classes of chemicals. And without going into a lot of detail, there's the, the barriers, I call them the P FOSS chemicals, the things in Teflon, that's a barrier for your frying pans. There's the barriers on your water resistant clothing, there's the barriers on their pizza boxes that keep the oil from going through all kinds of barriers are also endocrine disrupting. And then there's pesticides, which we talked a little bit about, which can be affect a whole range of hormones. And then the flame retardants are the other big class that we're very concerned about. The hormones that they affect are more likely to be thyroid hormone. So depending on what the class is, and what the hormone is, there's probably bill out there that's gonna affect the the presence, the amount, the delivery, the function of pretty much every hormone in the body. And it's through your research and others, that we're beginning to understand that it is exposure to these indican disruptors that may be responsible for the changes we're seeing in sperm count and other forms of reproductive health. Is that the is that the bottom line? I don't want to say responsible for I would say, contributing to or significantly contributing to, I mean, I study very specific things, you know, sure. And so I met him and so on. And so what I what I've done over a 20 year period, is just try to tease out how prenatal exposure to salads. And it's turns out to be in the first trimester, probably early first trimester, how first trimester exposure to salads, alter the genitals of exposed males, and how those alterations in adulthood can play out in terms of lowering sperm and fertility. So we see this in animals and our showed it in humans. And it also meshes with what we know about the chemical function of the salads, they are anti androgen, they do decrease testosterone. So the fact that, you know, we have this consistent picture, from the animal to the human to replicated human studies, I did this study several times other peoples have done it as well. And and then shown that, you know, when these changes are in place, the males have lower sperm count. We can talk about what the changes are, if you want, but but the point is to just pin this down for one class of chemicals and one set of output outcomes, right. Valid male, took me
at least 20 years, probably closer to 25 years and probably cost 15 to $20 million.
Yeah, your point is that in some ways that that how long do we we've got evidence, and it seems to me that we could be acting, this is my own personal opinion, but we could be acting on this. Because to wait for a definitive, as you point out it it time and money. It takes a lot of both. Yeah. Great. And then and then. So what the way the system is right now, chemicals are not tested for safety in the United States before they're marketed. And there are 1000s and 1000s of chemicals out there. 10s of 1000s, maybe 100,000. I don't know that nobody knows that number of chemicals that were, quote, grandfathered in, considered safe. They've been here a long time. They haven't done a lot of harm. Let's just make them. That's kind of the attitude toward the chemicals in commerce right now. Very few of them are regulated. In the EU. They're starting to do something different. They have a different set of regulations they actually require
manufacturers to prove the safety of their chemicals before they're put into the marketplace. And this is what's done with drugs. Let me point out it's not a foreign thing. And us it's done for drugs, drugs have to exhibit efficacy and safety before they're marketed. And we see that with a vaccine right now, right? All these vaccine trials, they're they're, they're proving safety and efficacy. And we need to do that for the chemicals that go into our bodies and our unborn children. You know, what could be more important, but we're not doing that. So I don't think we like you say have to wait for more evidence. We just have to start testing these things before they're marketed. Mm hmm. And keeping them out if they don't pass an exam? Yes, that actually test the way we're exposed.
Thank you so much. Dr. Shayna Swan, author of countdown, how our modern world is threatening sperm counts, altering male and female reproductive development, and imperiling the future of the human race. Thank you for being with us today. This has been fascinating and it's an important information that I'm so glad that you're helping us get out to everyone. I'm very appreciative and to our audience. Thanks for being with us, and we will see you next week.
Transcribed by https://otter.ai