A Global Fertility Crisis - Dr. Shanna Swan

so I got interested in the question of declining  sperm count way back in the mid 90s and a group   of us were on a committee we're trying to figure  out those chemicals that had been called endocrine   disrupting chemicals um chemicals that alter your  body's hormones the committee was asking well,   are they really bad for human health? That was  our charge to figure that out and so the committee   said to me there's this paper that just came out  a few years ago and it says that sperm count has   declined dramatically over the past 50 years do  you think we should pay attention to this and   i looked at the paper and i was skeptical i  thought ah that's pretty extreme and doesn't seem   to be a lot of data here and probably not but it  was important enough that i decided i would spend   a bunch of time figuring it out and so what i did  was i got the 61 studies that had gone into that   analysis and i looked at each of them and thought  of things like well maybe the method of counting   sperm had changed over time you can see how that  would lead to a lower count perhaps if you the   way you counted discounted fewer sperm that could  cause a trend not a real one but an apparent trend   or maybe the men in more recent years just had  poor sperm count because they came from different   populations maybe they were men coming in for  problems in a fertility clinic maybe the men were   fatter maybe they were smoking more maybe whatever  so i went back and i looked at all those things   and tried to put them in the model and  see if they accounted for the trend   and the surprising thing was that after i  spent six months on this analysis by the way   nothing changed not to the first decimal place it  was astounding i seldom have seen such a stable   result the decline was very significant it was  a straight line and it was very concerning so at   that point i said wow it seems to be something  going on here let me look into this further   and then i spent the next 20 years doing  that and i published a series of papers   which actually strengthened at each step that  result and finally in 2017 i published a study   with colleagues seven of us published the  study that said that there had been a 59   drop in total number of sperm in a sample  between 1973 and 2011 39 years i call   this the one percent effect the one percent  effect is a change of one percent per year   over a lot of years so if sperm count declined  50 in 50 years that would be one percent per year   but a 50 that was about what we saw we  saw actually a little worse than that but   a 50 decline means cutting it in half cut your  sperm count in half i don't think anyone wants   to do that right um it's the same thing with  testosterone it's also been going down at that   same rate one percent per year miscarriage or  pregnancy loss has gone up in women at that   same rate um and so on and so forth um we don't  have good solid data on all of these we have much   more limited time frames for these other things  because there are many more studies on sperm   count than there is on testosterone for example  trends but where we can look at it everything   seems to be progressing at about the same rate  of deterioration if you will of reproductive   function so wherever you look at it it's not  just man and it's not just women and by the way   it's not just humans because there are many many  species that have had their genitals disturbed   um by the same things that are affecting  us and we can talk about what that what   what those are and they've also had their  litter size decreased and they're you know   basically their species endangered by their  declining fertility and reproductive function   oh so the data overall is showing us for the  world as a whole back in 1960 an average couple   had five children that's the whole world now they  have a little less than half that 2.4 children   that doesn't sound too bad it's still over  replacement but when you dive into specific   countries like the us like asian countries you see  the situation is a lot worse and surprisingly mark   everybody is declining all countries are declining  in fact the countries you think well they're not   declining like east african countries they're  actually declining at a sharper rate because   they're starting at a higher point right so  um you have this overall decline in fertility   and normally the shape of the population in terms  of age is a pyramid so very few on top a lot on   the bottom a lot in the middle and the middle  supports the top and the bottom right but what's   happening now and you can see that in the pyramid  in asian countries is that the bottom is shrinking   pretty dramatically there's a bulge in the  middle and the top is growing hugely because   people have longer lifespans so longer lifespans  is a great thing i approve of that of course   but um in terms of support they're not going to  have the money for social security that's already   a threat in this country they're not going to have  the money for medicare they're not going to have   the resources to support this older population  in terms of you know medical treatment and   you're not going to have the labor force necessary  to drive the economy it's that middle sector that   drives the economy and it's going to have huge  economic implications and and many economists are   looking at that now it doesn't look good yeah what  is causing this is really so complicated i think   the first thing to say is that if we look at what  can be a cause of a trend overall whether it's   a cause in obesity or a cause in autism spectrum  disorder the first thing you might ask is genetics   and so if we look at this decline in sperm count  and fertility it's too rapid to be evolutionary   it's happened in two generations fifty  percent decline that's not going to be genetic   okay so let's just put that aside okay not  genetic all right so what are you left with   well causes are broadly classified into genes and  environment okay so now we're on the environment   side okay so now what makes up environmental  causes well i subdivide them into lifestyle   and that's very broad and i'll say  a little more about that and then   chemical okay so there are other things perhaps  but let's just talk about those so lifestyle   pretty easy to understand if a man or woman is  obese they're going to have more trouble getting   pregnant obesity is related to lower sperm  count smoking if a man smokes his sperm count   is going to be reduced if by the way his mother  smoked when she was pregnant with him his sperm   count is going to reduce so smoking is playing  a role large amounts of alcohol in a small town   called binge drinking is also associated with  lower sperm count stress surprisingly perhaps   is also associated with lower sperm count lower  fertility and so on so all of these come under the   you know in the bag of lifestyle factors something  we have some control over right then over here   are the chemicals and those are things that  we may or may not have control over and the   class of chemicals that i'm most worried about  are the ones that affect our body's hormones   and the reason is that reproductive function sperm  production pregnancy and so on are controlled by   the the hormones right everybody kind of knows  that you know your testosterone you're going   to worry about your estrogen if you're a woman  you know what your cycle is that your hormones   go up and down everyone knows that right  so all of that function is controlled by   the body's hormones now if you mess that  up you can imagine that you're messing up   the end product right the sperm the eggs the  pregnancy and that's what happens okay and   so you might ask well what can do that what can do  what can mess with that and that is a huge class   of chemicals which are called endocrine meaning  hormone disrupting messing up chemicals or edc's   i like to call them hormone hackers because they  sometimes pretend to be hacker you know hormones   they get in there they hack the hormone system  they mess with it and turns out that they're in   our daily lives in huge numbers huge numbers so  that's what i study mostly so it turns out that   after conception in utero is the most sensitive  time for the development of almost everything   some things develop later the brain is later the  brain continues to develop after birth and so on   body size develops later but the building blocks  of what's going to be your reproductive system   are really laid down early in the first trimester  so that's a very sensitive period and so what the   fetus is exposed to which really means what the  mother is exposed to because you know there's no   sort of barrier there's no barrier protecting  that fetus from what the mother is exposed to   gets into her bloodstream goes into the fetus  goes in and does its damage into in the fetus   okay so anything that the mother is exposed to  that's going to change her hormones or the fetus's   hormones are going to be concerning if you're  worrying about reproductive function and let's   dive in now just try to dive into the into  the fetus and look there at the developing   genital tract it's hard thing to think about  it's very you know microscopic but there's   this genital tract which initially is the same in  males and females genetic males genetic females   it's identical it's just a single ridge then  at a certain critical time which we know   exactly in the rat and less precisely in the human  but it's going to be early in the first trimester   the field testes starts making testosterone  this is very very important event for   everything that's going to follow in the  story so this undifferentiated general tract   if it's a genetic male gets the testosterone  and starts if you will waking up starts becoming   a genetically typical male okay so the  testing start developing and so on and   so forth all the all the parts start developing  what happens if there isn't enough testosterone   well that process just doesn't get completed  or if maybe the testosterone is too late   it won't get completed so what that means is  that it's going to be the default which is female   this is a hard thing to imagine you  know that the female is the default   but that's seems to be what it is and  and so if the male does not see enough   testosterone at the right time his journey to the  genetically typical male genitals is not complete   and i like to say he's incompletely masculinized  okay well i should just first tell you that this   was discovered in rats first by the way i want  to put a plug in here for rodent experiments   which are invaluable in learning about  human health we can't do it without that um   so i had heard from a friend on an airplane  flying to japan he said shauna you should   look at phthalates i said why should i look at  valids and he said well i'm a chemist i'm at cdc   we've been measuring these they're in everybody  including pregnant women everybody and   in the arm of the government that tests for  chemical toxicity they've shown that they disrupt   the reproductive development of the male in fact  they cause something called the phthalate syndrome   so my ears perked up because you know there's not  very many syndromes that are assigned at birth   there's fetal alcohol and there's the phthalate  syndrome so that made it sound really important   so i asked him what that was and he told me  that when a rat has been developing gestating   within a mother rat who's been fed phthalates at  the right time then his genitals are all smaller   they're all smaller and less developed so  his testicles might not be fully descended   and the penis might be smaller and the whole size  of the area is smaller well it turns out in all   mammals the genital size is 50 to 100 smaller  in females than males that's just how it is   some exceptions but almost all mammals  okay a particularly important measure is   something called the inner genital distance  it's just i don't know if you know what   the taint is the gooch the grendel those are  street terms for this distance that's the distance   from the anus to the genitals basically you  can measure it we measured it in our study they   measure it in the rat study so i heard about this  rat study and i thought that's funny i wonder if   we'll see that in humans and so i designed a study  to look at that it was the first study to do that   so it got turned out was kind of important  um so we had urine stored from pregnant women   and we sent them to cdc and we had cdc  measure what's called the phthalic metabolites   phthalates which are chemicals that lower  testosterone pass through the body really   quickly enter the urine the water soluble and  you can measure them so we did that for about 800   women have the cdc measure their phthalates  and then we said okay let's get the kids in   and measure their genitals seems like a  simple project right turned out it was   fairly complicated to do it was hard sometimes to  find the kids and bring them in and all that but   we did that and we found the phthalate syndrome  in humans so let me just reiterate we found that   when the mother had higher levels of certain  phthalates those that lower testosterone in her   early urine samples that her male child would have  genitals that were less completely masculinized   i hope that sounds dramatic because i  think it really is important and because we had to replicate this as you do with science  we wrote another grant we got another big study   we got another set of pregnant women got  their urine got their babies replicated it   and found the same result so now it's pretty  well established that that this is going on there's two kickers here one is these children  from our second study are now only 10 years old we   don't know how they're going to perform you know  in terms of fertility and function later on they   first study the kids are actually in their 20s  but they're really spread out around the country   and we're gonna try to get them in and get their  sperm count but we don't know if we'll be able to   do that however in the rat we know that if the  rat is born with a small in a gentle distance   then when he grows up he will still have for  his body size a small and a genital distance   it's like i have very small hands i've always  had small hands i'm a small person but but um   your portions of your body tend to grow  with you so you could ask okay an adult man   who has a short intergeneral distance what's his  sperm count like in other words does the shortness   of the inner general distance matter for his later  function you see if it doesn't it sort of doesn't   matter well it turns out it matters for a lot of  things it matters for genital birth defects he's   more likely to have undescended testicles if he  has a short agv he's more likely to have certain   defects of the penis one called hypospadias  he's more likely to develop testicular cancer   when he's a young man and he's more likely to  have a low sperm count and to be sub-fertile so   the bottom line the arc of this whole  20 years that i've been working on this   is that these chemicals when the mothers  exposed to them in early pregnancy   result in failures or limitations of  reproductive function in adulthood and   are undoubtedly part part of the explanation  of the decrease in sperm count and fertility so phthalics are in plastic they make plastic soft  and flexible so anytime you see a rubber tubing   um i just saw a survey of clothing in which  they measured phthalates levels in the clothing   and found that they were really high in the vinyl   raincoats and boots and anything that included  vinyl so any vinyl products shower curtains   tubing of any kind you'll see phthalates in  there but also foods that pass through phthalates   so think about a cow a cow used to be milked by  hand but then they started using milking machines   the milky machines you've seen them they have all  these tubes and those tubes contain phthalates   and so when the milk comes from the cow goes  through the tube goes into the container it   contains phthalates and the study in europe showed  actually significantly more phthalates in the milk   that was collected in that way compared to by hand  right so we know that any food that passes through   phallic containing tubing will contain this  phthalate and it will go into your body and it'll   go into the fetus and then the harm is done so  another way we get phthalates is in our cosmetics   and our personal care products because not only do  they make plastic soft but they also help retain   scent and color so any lipstick nail polish  um perfume scented laundry soap air fresheners   little tags that pine cones that you hang in your  car they're all going to have lots of phthalates   um and by the way they also increase crease  absorption so if you put a cream on your hand you   come back 20 minutes later the cream's gone right  it's meant to be absorbed phthalates help with   that they also help the pesticide get absorbed  into the plant so they're put in pesticides for   that reason so they're just all over it's hard  to find things that don't have these chemicals in   them um but by the way i should add that this is  only one class of endocrine disrupting chemicals   it's the one that i've spent the most time  on because it's particularly important for   the hormone testosterone but another class of  chemicals bisphenol a the phenols i should say   the bisphenols are kind of the opposite they make  plastic hard and instead of lowering testosterone   they increase estrogen so the kind of the  flip side if you will um and these are all   over the place too they're in the lining  of tin cans they're in um tooth sealants um   they're in our pizza boxes um they're in our  plastic water bottles and our baby bottles so   that's another class and then there's flame  retardants and then there's pesticides   and then there's something called the pfas  chemicals which are things like teflon   they're coatings so teflon water repellents paper  coverings that keep oil off like in your pizza   boxes right so everywhere you look and there are  hundreds of these um that are in our bodies right   now and many of them interact you know when you  go to the doctor your doctor is going to give you   a prescription she says to you what else are you  taking tell me about all your medications right   so you tell all there's nothing else and you out  of you and then you you tell all your medications   and then she thinks about that and thinks about  how they might interact with the medication she's   going to prescribe it's the same thing with these  chemicals they act together and often the hole   is worse than the sum of its parts just like you  wouldn't you know you could take one sleeping pill   you could take another sleeping pole start adding  those up it's not good i'm very worried about it   to tell you the truth i mean i think we do already  satisfy several of the criteria for endangerment   um which is a step way before extinction but um  we are threatened we're threatened and and um remember if you're a couple if you're a guy who's  trying to get pregnant your wife or partner wants   to get pregnant that's a right that's a basic  human right that you should be able to reproduce   if you want to no one's talking about everyone  should want to that's not what i'm saying but if   you want to you should have that opportunity and  that right and to have that taken away from you   from causes that are not within your  control is what i'm most concerned about so   i think there's a couple of good news items to the  story one is that a lot of the chemicals that are   harming us and phthalates in particular leaves the  body very quickly four hours five hours six hours   they're not sticking around they're not persistent  we call them non-persistent chemicals that's true   of bisphenol also so if we can stop taking them  in we're done with them and that's i think a   really good news story it's not like lead it's not  like dioxin pcbs and so on which do stick around   the other part of the story that's helpful is  that pat hunt who's a animal toxicologist in   the university of washington showed that  if you take a she use mice take a mouse   that's been messed up has poor reproductive  function because of chemical exposures and   then you clean up the environment of his offspring  and his offspring's offspring in three generations   you can restore reproductive function that's a  great story for a mouse or a rat because their   length of life is two years intergenerational  life gap is two years for us it's longer that   would be 75 years so we're probably looking at  a pretty long time to get it totally cleaned up   but we can start in that direction if we would  stop re-exposing kids that were exposed in utero   during their childhood and during their  adulthood then we would be on the road   to cleaning up our reproductive health hi thanks  for watching this episode of after school i'm   shauna swann i'm a reproductive epidemiologist and  i study how chemicals in the environment affect   our reproductive health for more than 20 years  i've been studying how these chemicals can affect   sperm count whether they're causing it to decline  and why you can read about this and other scary   declines in my book countdown thanks for watching  and i really enjoyed making this video thank you you

Channel: After Skool

Views: 1,150,027

Keywords:

Id: Uo-kSxHNSDQ

Length: 25min 15sec (1515 seconds)

Published: Tue Oct 12 2021

Reddit Comments

[u/leftyghost]

Look at the amount of skin exposed to the sun in the thumbnail picture and you’ll get half an idea of why T is dropping.

[u/partyguy42069]

It’s in the water, it’s in the air, it’s in the meat. It’s indirect, it’s indiscrete, it’s inconsistent, incomplete.

Plastics, phthalates, parabens, PCBs, pesticides, phytoestrogens. Animal waste runoff is rife with estrogens contaminating drinking water.

I know my mom drank a lot of milk when she was pregnant and who knows if she boiled plastic baby bottles per directions to sterilize them or something. I’m a sensitive person to many things and I’m sure environmental toxins are not an exception. It’s too hazy of a line to determine what personal qualities can be ascribed to genetic predisposition or environment but it’s certain that masculine humanity is trending weaker and more frail. Endocrine disrupters are causing massive mental health and developmental problems from my perspective. It’s too bad the problem is so ubiquitous in our culture unlike how Clarence Patterson fought successfully to get Lead out of gas in the 70s after serious damage was already dealt. This problem isn’t going away anytime soon with a magic bullet. Who knows what all these environmental chemicals do to all of the other hormones in our symphony of finely tuned biological functions.

I’m 29 and got on TRT 2 weeks ago. Switching clinics and about to introduce HCG so that I can get off briefly and have kids someday hopefully. HCG is mostly know for ramping up production in pregnant females so who knows what kind of experiment I’m playing on the expression of my genetics to be passed down. I don’t care though. The struggle is too real to keep going on struggling with how much effort I have been exerting to keep my baseline high enough to function. Could be some other things going on with me. I’m trying this as a trial to test my suspicions.

People focus on girls not wanting to have kids as a cultural shift but there is something deeper and more sinister going on beneath that. I honestly hope this is all one phase in an intentional shift to thin the herd. I really hope we’re not that stupid to poison ourselves out of existence by incompetence.

[u/Master_Hunter_7915]

What's the cause so I can double my testosterone /s

[u/gastrocraft]

It’s directly correlated with obesity rates. In populations that have not seen obesity skyrocket, the testosterone has not fallen. There is not a population that I’m aware of that hasn’t had some level of obesity increase though so the results show decreases still but it’s proportional to the percentage of the population that have unhealthy BMI.

[u/Ymysohighguy]

Global warming, responsible for a HUGE increase in heart attacks. Lol. Don’t compare it to that dude.

[u/DrWilliamHorriblePhD]

Ok so what did normal bloods look like 50 years ago

[u/Usagii_YO]

Shitty diet and micro plastics.

[u/WorldWideDarts]

No wonder so many dudes are painting their nails nowadays

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