Autism: The Real Reason It’s Going Up

Hi, I'm Wendy Zuckerman, and you're listening to Science Faces. This is our last episode for a little bit. We're going to take a short break until September, while we work on new episodes. So that means if you have an idea, something that you want us to versus, you've got to tell us. There's a lot of ways to do it. You could do it on social media, Instagram, TikTok. There's an e-mail address. It's all in the show notes. So if you've got an idea, there's something that we have to versus, please let us know. We absolutely love hearing from you. Now, on with the show, today's episode is all about autism, because we're asking, why does so many folks have it these days? Rates of autism have been going up and up for decades. But then a couple of months ago, the CDC released the latest numbers, catapulting this issue into the spotlight. A brand new report out today from the Centers for Disease Control finds a dramatic rise in autism diagnoses among children. An alarming spike in the number of children diagnosed with autism. New data just released shows a 15% jump in just two years. The CDC report found that one in every 31 kids looked like they now had autism, which is nearly five times more common than it was 25 years ago. And the rates in boys were even higher. Health and Human Services Secretary Robert F. Kennedy, Jr. says this is an epidemic. This is part of an unrelenting upward trend. Revalence two years ago, the answer is very clear. And this is catastrophic for our country. And it's not just in the US. In Japan, Canada, Australia, Europe, rates of autism have been going up to. And now there is this huge fight brewing as to what's behind this. Why do so many people have a autism these days? RFK, junior reckons. This is coming from an environmental toxin. And somebody made a profit by putting that environmental toxin into our air, our water, our medicines, our food. There's all these different theories about what's causing this from vaccines to pollution and a whole bunch of other stuff. Can more screen make your child autistic? A new study says yes. It might be microplastics, the forever chemicals. Living in an area with high levels of air pollution may be linked with the woman's chances of having a child with autism. But then there are folks saying, "Whoa, whoa, whoa, whoa!" There's actually a much simpler explanation here. And it all has to do with how we diagnose autism in the first place. So who's right? What is going on here? At a recent press conference, RFK Junior said that we're going to start to have answers on the root cause of this epidemic by the end of the year. But Christmas has come early. 'Cause today, on the show, we are going to find out what's happening. When it comes to the rising autism, there's a lot of fingers pointing at lots of different things. More screens, microplastics. But then there's science. Science versus autism is coming up to staff to the break. (thunder rumbling) (thunder rumbling) Welcome back. Today, we're looking at autism and finding out why the numbers of people being diagnosed with it have been going up and up. To tell us all about it, we have Cedya, producer, Varyl Hord. Hey, Varyl. Hey, Wendy. All right, Varyl, can you just tell me what exactly is autism? I just feel like people kind of throw it around, diagnosing their friends with it, their friends' children with it. You know what I mean? What are we talking about here? Well, it can show up for different people in different ways. But generally, a lot of autistic people will have a harder time communicating. So that's a big theme. And then there's other stuff that shows up a lot too. Like, you might have really specific intense interests or a harder time when your routine is disrupted or more intense reactions to really annoying stimuli, like really bright lights are allowed noises. That kind of thing. And then our big question of this episode is why do so many more people have it these days? Yeah, what is going on? When I started talking to scientists about autism and general about what causes autism, there is one thing that came up right away. Genetics is sort of the elephant in the room that you can't ignore. Genetics. Yeah. So this is Professor Brian Lee, epidemiologist at Drexel University. And he said that a huge part of whether somebody will be autistic is just passed down to you. It's in your genes. And we know this from looking at studies on families. So if one sibling has autism, the other siblings are more likely to also have it. And then if you look at identical twins who basically have the same DNA, it's even more likely that if one identical twin has it, the other one is really likely to have it too. And so based on all that, scientists have figured it out, how much of autism is inherited? And it's-- Some more between 70 to 90%. Whoa. That's huge. 70 to 90%. Yeah. Yeah. And we don't really know all of the genes that are involved. Sometimes it might be that there are hundreds of genes that are all working together to up that chance that someone will have autism other times. It'll just be like one particular genetic quirk. But yeah, it's genetics is huge. I guess in the context of this rise in numbers that we're seeing though, genetics can't explain why so many folks would be diagnosed with autism now, right? I mean, because why would we suddenly have so many more autism genes in the population? Well, actually, there is one thing that has changed. So parents are having kids at older ages now. And that might be introducing it genetic changes that can like up the chance that their kids will be autistic. And so how old are we talking here? Well, Brian has studied this. And so he did like a back of the envelope calculation with the latest numbers for me. OK, so overall in the US, about 3.2% of kids are autistic. So that's kind of like the baseline chance on average for autism. Yeah, so 1 in 31 kids. Yeah, it works out to 3.2%. But if you're a mom over 40, we think that the chance goes up from 3.2% to something like 5.6%. That's not nothing. And then what about the other side of this, the spur, the spur? It's actually a smaller increase for the dads. But yeah, it slowly goes up a little bit. So could this explain why we're seeing higher rates of autism across the country and around the world? Well, a lot more people are having kids later in life, like the percentage of births to women who are older than 40 has basically tripled since 1990. But overall, it's still a really small percentage of like total births is like 4% of all the births in the US are from moms in their 40s. So I asked Brian, like at the end of the day, how much does he think this older parent thing can really explain the increase in autism cases? It's certainly going to contribute some portion, but it's not explaining the lion's share. It's not going to explain the lion's share. OK. So what else could explain the lion's share? We've got like the Miyakats share covered. Lion's share still out the open. Right. So that's the big question. Because genetics might kind of set the stage for whether or not someone will have autism, but there is this idea that maybe you need like a trigger to actually make it happen. And scientists have been finding lots of things that might sort of be that trigger and up the chance that someone will have autism. A lot of the things we're finding kind of come into play when someone's a fetus, so things that happen during pregnancy and utero, so like if a mom gets an infection, if there is birth complications, taking certain medications while you're pregnant, like there's an anti-seasure medication that will up the chance that someone will have autism. But like a lot of that stuff doesn't really explain why autism would suddenly be more common in the last few decades, right? Oh, because pregnant folks aren't taking more of those meds. No. Yeah, experts told me they didn't think that this stuff would make a huge dent. There's maybe one exception to this, which is that if you're born prematurely, like very prematurely, you're more likely to have autism. And there are more premature babies that survive now. So maybe that's contributing a little bit to the rise. But the researchers have talked to say that like, oh no, this is such a small proportion of people with autism, that like that really can't explain these huge rises that we are seeing either. OK, so then what about these things in our environment? The stuff, I guess. RFK Jr. talks about environmental toxins, which he said could be in our air or our medicines. And I suppose we could put plastics in there too. What do we know here? - Yeah, we asked RFK's team about what specific environmental toxin he was talking about. And a spokesperson told us that, quote, "Everything is on the table." So I asked Brian about this. When RFK Jr. was talking about why autism is so pervasive, he said, quote, "This is coming from an environmental toxin." What do you make of that? - I know of his weird conspiracy theory type attitudes on vaccines, and I'm wondering if that's code for we need to do another vaccine study. And if that's what he means, I would be very horrified because that would be a tremendous waste of money to go basically beating a dead horse at this point. Vaccines do not cause autism full stop. - It has been studied. It has been taken seriously. It has been studied and various different vaccines, various ingredients and vaccines. And no, we cannot see a link here. But there are other potential things that are in our air and our water that probably weren't 25 years ago, right? - Yeah, no, and there is a lot of research looking and saw their stuff that is in our environment and might be linked to autism. Brian said that one kind of hot area of research is air pollution. Like a big review just found that there might be a link between being exposed to certain types of air pollution during pregnancy and the kid later having autism. - Oh, how would that happen? So pollution are these tiny little particles right that we breathe in and it could be that they're getting past the placenta and into the brain as it's developing and then maybe kind of changing the brain, like maybe through oxidative stress or neuroinflammation. But the kind of pollution that's linked to autism has generally been going down over the last couple decades in the US. So like that doesn't explain why it's been going up. And it's sort of similar with heavy metals, which is something a lot of people on the internet are worried about right now. There is some research that says maybe any exposed to lead, for example, might up the odds for autism, but lead and other heavy metals have generally been going down. - Oh, okay, so plastics. Plastics have been going up, right? - Yes, plastics have been going up and there are a lot of studies that have looked at a potential link between plastics and autism. So researchers will look at the blood or pee from a pregnant person and look for chemicals, like phallates or PFAS or forever chemicals. And then they'll ask, like are the kids who are exposed to more of this stuff in utero? Are they more likely to show signs of autism later after they're born? - Yeah, yeah, yeah, and what do they find? A few studies say yes, but the vast majority of them find no connection. - Hmm, so, okay, no, there's no smoking gun here, thus far for the lion's shape, because maybe increased cases here or there, but we are looking for something that could really explain, like quite a large number of people now being diagnosed for the autism that we're not before. Screens is the other thing being thrown out? - Yeah, I looked into screens and was surprised that there actually was some research on this. - Why, why, which I don't know. People blame everything on screens and I was just like, "Eh, I don't really buy it." But then, like, let me tell you what happened, though, when I talked about it with this researcher. - Uh-huh. - I'm Karen Haffler. I'm a researcher at Drexel University. And unlike me, Karen was like, "Well, it actually makes total sense to look into screens, particularly when you look at the timeline here." - How has the world changed over this period of time? Babies, children used to be first exposed in the 70s at about four years of age. That's the first time they watched any television by about 2006, it was at four months of age. - But it's not just that the timing fits here. There is some evidence linking screens to autism. Like there are studies that have found that kids who are exposed to more screen time when they're really little, maybe like a few hours every day when they're one or two. Those kids are more likely to either show autistic traits later or even be diagnosed with autism later in life. - Mmm. And that's not that much screen time. What on two hours, right? - Yeah, like some studies find even that much might make a difference. And then Karen did this really interesting pilot study looking at whether getting families to cut down on screen time might decrease their autism symptoms. - Right. - It was really, really tiny. So they only had nine families. But I thought it was interesting 'cause what they had them do was pretty dramatic. So they chose families with autistic kids who are watching a lot of screen time. So before the study started, the screens were on for an average of five and a half hours every day. - Wow. - Yeah. - Then during the study it was six months long. They got them to cut it down to like five minutes of screen time a day. - Not even a full episode of bluing. - No. - Exactly. And so she looked to see if this had an effect. And it seemed like it did work. Like the kids had a decrease in some autism-related behaviors by the end of the study, specifically in social skills. And repetitive behaviors. So before the study. - The children at the beginning, a lot of them didn't really pay attention to their parents. They might be spinning wheels on a car or lining up items or just distracted with sensory like flapping or looking at lights. Not really interested. - And then after basically no screen time? - The eye contact got better. They wanted to be with the parents. They started paying attention to people. - Mm. That feels promising. - Yeah. But then Karen told me about something that really changed the way that I thought about the study. So cutting down on screens was a big part of the study. But it wasn't just turning off the screens. We met with them for one hour every week and worked on strategies to help them engage their children socially. So eye contact. So if a baby cools or babbles, then the parent would smile back or maybe imitate the child or we would suggest that they hold interesting items to their children up to their eyes. And if the child looked at them, then say, oh, great looking. Oh, I love to see your eyes. Really positive reinforcement. And so from other studies, do we know that that kind of positive reinforcement with a kid with autism helps them? Like would you expect to say these results if you forget the screen chat and you just do the positive reinforcement? - Yes. I have a very satisfying study for you now because Karen told me about a study where they basically did that. - Oh, okay. - So this one was a larger proper randomized controlled trial with about a hundred really young kids and they had started to show some signs of autism. And what they did in the trial kind of reminded me of a lot of the things that Karen did in her study 'cause it was like teaching the parents had to pay attention to their kids really closely responding to them and interacting with them. - Right. - But they didn't tell them anything to do with screens. - Perfect, great. Okay, so then what happened? - Well, fewer of those kids were diagnosed with autism later. - So then what do you think? How much do you think screens are playing a role here in this so-called autism epidemic? - Well, it is a little tricky 'cause like there are also other explanations why we might see a link between screen time and autism. - Right. - Like we know that a lot of kids who are autistic really enjoy watching screens. So maybe it's just that someone's already autistic and then maybe their parents put the TV on more for them because they see that they're really happy. But that's not to say that screens are totally innocent here 'cause you can also imagine that maybe there's a kid who is already on the autism spectrum and is watching hours and hours of screen time every day instead of interacting with other people. Maybe they're more likely to end up with an autism diagnosis because their social skills aren't getting like a workout. - Mmm, that makes sense. - But I think bottom line you don't seem to think there's evidence that screens are really behind this, this epidemic, you know? - Maybe a little bit, but it's really hard to say how much. - Okay, so here's where we're at. I don't know, I feel like we have not gotten that lion's share of these cases yet. I mean, there's more me a cat dinners here and there. - Okay, but we're missing something big still. - Yeah, yeah, that's what we're gonna look at after the break. Something big. Welcome back, today on the show Autism, what is causing the rise in cases? We talked about how there's a lot of things people point in the finger at from plastics, which is maybe play some role here, but it's definitely not a slam dunk. Screens are no, screens are a maybe, people having kids when they're older, playing some role here, but not that much. Meryl, you promised me something big, the lion's share, I feel like we've earned it. Yes. Well, so one idea is that this actually just has to do with the way we're like deciding who has autism and who doesn't. And that basically we've decided a whole lot more people who would otherwise not be classified as having autism now all of a sudden, you can join the party as well. Yeah. Yeah. And this is something that RFK Jr. really rallied against in his speech. He said that the idea that we are somehow not catching all these cases in the past is like actually kind of insulting to the doctors who are practicing back then. Doctors and therapists in the past were not stupid. They weren't missing all these cases. The epidemic is real. So to get to the bottom of this, I decided to call up a scientist who has been diagnosing autism for decades. This is Katherine Lorde, professor at UCLA. Did you ask her if she was stupid? Yeah. That was my first question. But actually, my first question was about something else. Okay. I was told by one of your colleagues that you are the diagnostic queen when it comes to autism. Oh, dear. Well, with other people not single-handedly by any means, I work to develop the most commonly used diagnostic instruments that people use when they diagnose autism. That's where that came from. She's also the diagnostic queen because she's been in this field through the like absolutely wild changes that have happened over the past few decades. When it comes to how we, how we do this, how we diagnose autism, which I know it kind of sounds like a snooze fest, but it's, you know, it's actually the story of like how our understanding of what autism is has evolved. So let's start in the 1960s. Back then, we weren't even sure if autism was its own thing or if it was part of schizophrenia. Oh. And this is kind of what we thought autism looked like then. I mean, I think in the 60s, a person with autism would often be not verbal, like not talking and would be quite severely intellectually disabled. We were very focused on things like flapping your hands and looking at your fingers and the things that you can see right away. This is when Catherine got into the field as an undergrad and she loved working with autistic kids and finding ways to connect with them, even, you know, when they weren't verbal. But then sometimes a kid would come in who would really challenge the idea of what someone with autism was like, like Catherine remembers this one kid. Oh, I saw this little boy who had all kinds of language that just poured out of him and in those days we had them parents sit in another room and watch us and so he was not happy about that at all. He was about four and he had a lot of repetitive language and his nose was running and he started talking about, I don't want to be a rainbow, I don't want to be a reindeer, I don't want to be a reindeer, running reindeer, I want to be a reindeer. And what he was talking about was he was crying and his nose was running and he had these phrases and he was trying to figure out how to say, "You're making me cry." And people were like, "Boy, I don't know if he could be autistic." And he was as autistic as you could be. So what made him, what else about him made it clear that he had autism? Well, now we know that like, it's not necessarily that you don't have any language at all, but you know, the way he used language was really different. Like, he would often repeat phrases over and over again. And so yeah, it's like not as simple as we thought. And so that was the 1960s, but that's kind of like limited definition of autism stuck around for a really long time. That you needed these severe traits? Yeah, like really severe traits and it was often accompanied by intellectual disability. But then, even in 1980, this is when you see autism get its own entry in the DSM, which is the like Bible for diagnosing psychiatric conditions. So now it's like, it's not part of schizophrenia anymore. We got that right. But the description of autism is pretty intense. Like it says, quote, this disorder is extremely incapacitating, unquote. But then there's kind of a turning point. The next version of the DSM comes out in 1987. So by then, scientists had started to think about autism as like a looser kind of collection of traits. Like, we still think that having trouble communicating is like a hallmark of autism. But maybe it's also that you're really interested in a specific thing. So getting very focused on something, you know, that could be anything. I mean, it could be the same things other kids aren't interested in so, you know, dinosaurs. But it also could be Scottish clans or we had somebody who loved newspaper editors. He was an expert on who were the editors of the major newspapers and could recite that. So it's, and it's not bad to have an interest. It's just that not being able sometimes to to rain it in if other people are not so interested. So this is, I mean, the late 80s is exactly when Rainman came out. Yeah. Right. And I mean, I'm sure with 2025 eyes that movie does not hold up well. But it does show how much the image of autism, at least in the public's imagination, changed so much already by then. You know, he was a character that was a genius in some respects. I mean, like, he could memorize the phone book, right? Yeah. And just generally, we end up getting to this place where just because your autistic doesn't mean that you're incapacitated, like it used to be described, like in some cases, you might be better at things than neurotypical people. And so we can see this expanding and expanding definition of autism. And they're also kind of going along with this. We used to think that Asperger's Syndrome was something different. Right. Oh, yeah. And now that's been rolled right up into autism spectrum disorder. It's all part of the same thing. Uh-huh. Okay. But I feel like this idea of what autism is is still changing right now. It's like the tectonic plates are still shifting and in, you know, another 50 years, it could just look different again. So what, what is the sort of suggestion here is that this autism epidemic, these new cases of autism, it's actually just because we have changed our definition of autism when not just capturing these folks who have real difficulty verbalizing, communicating, maybe also happen to have severe intellectual disability. We're now opening up the definition to include folks who are neurodivergent in more subtle ways. Yeah. And, but that, that would mean you should be able to see that in the data, right? And yet RFK Jr says that most of the new cases are, quote, severe, which would go against this idea that, oh, it's just our changing diagnosis, right? Yeah. He's kind of like, no, now is when we're seeing all these severe cases, like he painted this really dark picture where he called this tragedy and said that, quote, autism destroys families. These cases now are severe, so about 25% of the kids who are diagnosed with autism are nonverbal, non-toilet trained. And yeah, that's like in pretty stark contrast to this idea that autism is actually just going up because of this definition kind of expanding. Yeah. So who's right? I mean, do we have any numbers here? So a couple of researchers told me like, oh, you have to talk to Marine Durkin because you just presented this work at this huge autism conference that looks at that exact question. Oh, cool. So, yeah, she's an epidemiologist at the University of Wisconsin-Madison. Hi, Merrill. Can you hear me, okay? Hi, I can hear you. Great. So Marine basically found a new way to like dig into the data to look at what kind of kinds of autism cases are the ones that have been going up. Great, great. So she did this. These are eight-year-old kids from across the country and the kind of time frame she's looking at was from 2000 to 2016 and what she does is kind of divide autism cases up into different buckets where on one end, you have what people might think of as like severe autism. So this is somebody who needs a lot of help when it comes to stuff like going to the bathroom, getting dressed, communicating their needs, that kind of thing, they're like day to day functioning. - Yeah. - And so actually let's start there and find out like what Marine saw when she looked at those kids over time, this group. - Did not increase at all. - It did not. In fact, it declined its site back then. - Wow. - But it didn't increase. - It did not increase. - Mm-hmm, mm-hmm, mm-hmm, mm-hmm. - And when she looked at what cases were going up, it was a totally different group of kids. - The biggest increase was those with no actual measurable functional limitations. - Oh. - Yeah, that biggest increase was in that group, 'cause that was a very small group in 2000. - Mm-hmm. - Yeah, so. - Right. - So these are kids who are autistic, who don't actually need any more help than neurotypical kids in their day to day life. And that Marine also saw a rise in kids who maybe need like a little bit more help. And this research isn't out in a journal yet. It's a peer review now. But she presented it at this conference. So let me show you this graph that she presented there. That kind of made a big splash. - Uh-huh. So this is looking over time from 2000s. It's 2016. - Oh, yeah. And you can see really clearly that the severe cases they have dropped a tiny bit, maybe barely statistically significant. She got the air buzz there. But it's really these milder forms. That's what. That's the lion's share, Marrow. - Yeah. We found it. - We found it. We found it. - So I asked Marine. And so these were the cases that we were kind of missing decades ago. - It appears that. Well, we know that's true. That as the definition of autism is expanded over time, we're including a wider spectrum. - We did reach out to RFK's teams to ask them what they made of this research. They didn't address that question, but instead they doubled down on the idea that there is an environmental toxin that's causing this. I also asked Katherine Lord about this. If we are labeling more people today with this label, how much does that really matter when it comes to explaining why it looks like autism has gone up? - I mean, I think it accounts for most of it. And I think all of us worried that we're consuming plastics and things that we wouldn't choose to eat or breed. But that can't account for most of what's gone on. So in the press conference recently, Health and Human Services Secretary Robert of Kennedy, Jr. basically kind of put food this idea that it is just about changing diagnosis. So is he wrong, basically? - Yeah, I think he's wrong. - And there are other things that might explain why we're seeing more and more cases of autism that could become standard to screen kids when they go to the pediatrician for autism. There's also just more awareness. A lot of researchers told me they think that could be playing a role here. - Right, yeah. - And that leads me to the final thing I wanted to mention because like now that we've got this bigger understanding of autism of what it can be, it's really shifted the picture of what an autistic person could look like. So in the past, there is a strong bias towards diagnosing boys with autism. - The hardest thing was that if you're female, you're not autistic 'cause it's very, very rare. - So this is Tina Gasner, researcher at Drexel University. And yeah, she told me that she's autistic and she wasn't diagnosed until she was 40. And she said that for so long, doctors had this idea that autism was pretty rare in girls where today you see that ratio sort of leveling out. And it also used to be more common to get diagnosed with autism if you were white, but those numbers are also leveling out. So now in the US, white kids are not more likely to be diagnosed with autism compared to other racial groups. And it's not necessarily that these people weren't getting any diagnosis at all. In a lot of cases they were getting misdiagnosed with something else. This happened to Dina. - I was misdiagnosed with bipolar. - Oh wow. - That is not uncommon bipolar and personality conditions are often diagnosed and autistic women before they get their right diagnosis. And the problem with that is the medications that come with that. - Yeah, so for Dina, even though she never had bipolar, she was put on lithium. - What did the lithium feel like? - Oh, I was completely dysfunctional. You know, I could not, I just wasn't a human being for that time frame. And so I finally found a doctor who was actually treating my children who said, I think you might want to reevaluate where you are. And he saved my life. Gosh. - Yeah, researchers have told me that this is, this is actually kind of a common thing that, you know, a parent will take their kid in to get diagnosed with autism and then they'll walk away with their own diagnosis. That was missed years ago. - All right. Which goes back to this idea that genetics is so important to this epidemic that we're seeing because now instead of one case, you have two cases. - Yeah. - But you know, like it's funny, we keep using that word epidemic to describe what's going on. And I don't think that's actually the right word to describe like the rising cases. I mean, lots of scientists have told me that like the real epidemic here is that we are failing so many autistic people who need better services that there's an epidemic there. But the idea that the rising cases is in and of itself a tragedy or an epidemic. I asked Dina about that. How do you feel about the fact that we're seeing more and more people being diagnosed with autism today? - I think it's fantastic. - Yeah. So for Dina, it was like the start of really understanding who she was and also helped her find a community of other autistic people and also other moms of autistic kids since her son is autistic too. - I was seeing that mothers of autistic kids were often abandoned by their girlfriend network and we need nurturing and we need community. And so I started a group called Bargarita Moms and we drank Margaritas and we went to see Magic Mike. (Dina laughing) And our rule was, you're not allowed to talk about your child but you can talk about your undiagnosed waspened, you know? (Dina laughing) And we had fun. And so we're seeing this rising army of these kids really neurodivergently intact, healthy, well-adjusted autistic kids that are coming up and my grandma jeans get all fired up. You're like, oh, that's awesome. Let me see your child dancing to Taylor Swift. It's joy, it's autistic joy that's coming out of this newer population. And so that's why much of our community is pushing back on these highly stigmatizing languages, you know, assigning tragedy mindsets to this population. When we experience access to communication, unconditional love and meaningful usable supports, we have healthy, well-adjusted, but autistic people. And that's a good thing. - Yeah. - Well, we've solved the case of the so-called autism epidemic. - Yup. - Merry Christmas. (Dina laughing) - Thanks, Marrow, thanks Wendy. - But science passes. - So, science passes is gonna be on a little break until September while we work on new episodes. And I thought to celebrate this last episode of the season, I would invite the team to our citations chat. - Yay. - Hi everyone. - Hi. - Hi. - No. - And a baby. - And a baby's here too. - How many citations are in this week's episode? - Six. - Six. - Six. - I didn't know. - Aketty, what was your favorite moment of the season? - I think my favorite moment of the season has to be meth. Ooh, meth. - I just like, it's like a new vocal stem. I say it at least like a couple times a week for sure. So, Michelle, favorite moment. - I really loved bird flu and learning about manure legumes. That was just the weirdest fun fact in the world. - Fine. - I just have to pick the fact that we finally made our episode on squirting. - Of course. - It was just a delight. And it was a long time coming. - Who? - Sarah. - And I have to say the carnivore diet episode last week was just so fun. Something about the top. It was just so like, broy and hardcore. I just like, it really made my dopamine flow. - All right, then to cap us off the season, we'll be back in September. Wasted, I didn't touch to pitch. Us ideas are all of the show notes. Please do that. The citations link to the transcript. It's also in the show notes. But to cap us off, all right, everyone. Let's say primal. - Primal. - Primal. Oh, is there a better one? Is there a better science one? - You're a viewed literature. (all laughing) - Thank you so much for listening, and we will see, and you will hear us very, very soon. Thanks guys, bye, bye, bye, bye. - Bye, bye. - Bye. (upbeat music) (upbeat music) - This episode was produced by Merrill Horn, with help from me Wendy Zuckerman, a Keri Foster Keys, Michelle Deng, and Rose Rimler. We're edited by Blithe Tyrell. Back-checking, research assistants and consulting by Erica Akiko Howard. Mixed and sound design by Bobby Lord. Music written by Emma Munga, so wily, Peter Leonard, Boomi Hidaka, and Bobby Lord. As special thanks to the researchers that we reached out to, including Professor Karen Pierce, Professor David Mandel, Professor Deborah Builder, Professor Frederique Bonet-Brio, Dr. Helen Taeger Flussberg, Dr. Isabella Della Lara, Katherine Byrne, Professor Sven Bolte, and Dr. Whitney Washington. Special thanks also to Lynn Keys, and Bella Viseca, Chris Souta, Elisean Dillon, Jack Weinstein, and Hunter, Joseph Lavell Wilson, and the Zuckerman family. Science Versus is a Spotify studio's original. Listen to us for free on Spotify, or wherever you get your podcasts. We are everywhere. If you are listening on Spotify, then follow us, and tap the bell icon so you get notifications when new episodes come out. We'll be back in your ears in September, and I'm Wendy Zuckerman, and I'll back to you then. (upbeat music)