The science behind autism

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Hello, delightful, curious-minded listeners, and welcome to the podcast of Inside Science with me, Victoria Gill.

The program was first broadcast on Thursday, the 25th of September, 2025.

This week, we're asking why America is sending astronauts to circle the moon when NASA landed people on the lunar surface nearly 60 years ago.

And we'll be taking a moment on the the side of a Scottish loch as we search for a very special bird of prey.

First, you will have heard by now about President Donald Trump's comments about paracetamol.

With the backing of US Health Secretary Robert F.

Kennedy Jr., the US President made a statement saying that pregnant women should avoid taking acetaminophen.

That's the same drug as paracetamol, and it's known more commonly as Tylenol in the US.

His claim?

That it increases the risk of autism in children.

But today, with so much misinformation being shared, we want to take the time to look at the the real science of autism.

What does the evidence say about what causes this complex disorder?

Joining me is Laura André, a professor of developmental neuroscience at King's College London.

Hi, Laura.

Thanks for being on the programme.

Hello.

It's great to have you.

Can we just start with a little bit of the background?

This isn't the first time we have heard about a single factor being implicated as the cause of autism.

You know, possibly the most infamous link was with the MMR vaccine.

That was debunked.

Could you give us an overview of what is thought to play a role, a causal role in autism?

The simple answer is that it is mostly genetic.

It's very complicated.

There are probably at least hundreds of different genes that have now been implicated, ranging from very rare genetic variants to perhaps some more common but sort of low impact.

Having said that, it does seem likely that there may well also be contributions from environmental risk factors.

So for example, maternal infection or there's a drug called sodium valpirate that's used to treat epilepsy, that when given in pregnancy, possibly increase the risk of autism.

We don't understand as well the environmental risk factors, and there definitely needs to be more research there, but it seems they probably do play a part.

And then the last thing is probably just to mention that it's quite likely that just chance plays a role as well.

So, the developing brain is really complicated, a lot's happening, lots going on, and you can imagine that sometimes just by chance, you kind of go down one pathway versus another.

But genetics is by far the biggest biggest contributor to risk of autism.

And what made researchers think genetics was such an important factor?

It really started with just looking at families.

So it was quite obvious that if you had one child with a diagnosis of autism, then the probability that, say, your second child might also get a diagnosis was higher than from the rest of the population.

Building on that, then people started looking at these twin studies.

So comparing identical twins with non-identical twins and seeing what the chances are that if one twin has autism, the other one does as well.

And those kind of studies indicated that the heritability is probably somewhere between kind of 60 up to about 90%.

So basically a huge part of the risk of developing autism seems to come from your genes.

And have those twin studies pinpointed the specific genes?

How specific can we be about the genetic basis for autism?

Well yeah, we can be actually be quite specific.

So the twin studies didn't.

So what they would do is they initially they would have to find families with multiple people affected with whatever particular disorder you're interested in and then try and work out very slowly and laboriously which genes seem to be associated in all the people who were affected.

But then as technology advanced, particularly over the last two decades, we've started to be able to really identify the genes involved.

Initially, looking for these so-called deletions or duplications where you've basically got little chunks of DNA that are either missing or duplicated.

And weirdly, we're all walking around with these all the time, but some of these are associated with disorders such as autism.

And then, more recently, with the advent of high-throughput sequencing, where we can read very quickly the whole of a person's genetic code.

And based on that, we've been able to identify probably, you know, in the order of hundreds of genes that contribute to the risk of autism.

Where does that leave us now?

Does anything particular stand out?

You know,

what do we understand about the driving forces behind autism?

Exactly.

So of course, you can imagine, once people started realizing that it wasn't as simple as just, you know, one or two or three genes, everyone started looking for patterns.

You know, do these genes encode for proteins that do something and have something in common?

And broadly, interestingly, we've been able to kind of put them into roughly two buckets, if you like.

One of those buckets is what's called transcriptional regulation, which basically just means that they regulate other genes, which is a bit unhelpful.

It kind of just kicks the ball a bit further down the road.

But the other bucket is something to do with the synapse.

And the synapse is the connection between neurons, which are the brain cells that are kind of doing all the important stuff in your brain.

That really tells us that during development, as all these synaptic connections are forming, something is probably affecting that.

And that gives us some clues as to what may be actually going on, you know, downstream of these genes.

Right.

And can we even say, can you look at the neuroanatomy or physiology of a brain of someone with autism and someone who doesn't have autism and kind of compare the two?

Can you

see what's different or see how the workings of an autistic brain are different?

So people have tried a lot.

So there are loads and loads of studies that have tried to do exactly that.

I would say it's quite hard to pinpoint any one specific thing.

There are quite a few ideas ideas out there, but it's clearly very complex.

And it's probably worth mentioning that autism is probably not a single disorder.

This creates a problem when trying to look into people's brains because, you know, you see lots of different things going on.

And, you know, what's true for one person might not be true for another person.

Whilst people have found a few things, it's been very hard to replicate that over very, very large groups.

And maybe just because different people have different forms of this.

And

I should say that many people with autism and some advocacy advocacy groups say that this isn't something to be cured.

And when listeners hear about looking for underlying genes and causes, they might think of looking for a cure.

You know, why look for those genetic underlying causes of autism in that context?

As I said, there's a huge spectrum.

So there are autistic people who are clearly completely fine and would find the idea of working towards a cure, you know, unwanted and absurd.

And I think that's totally fair enough.

But there are also people right right at the other end of the spectrum of severity who don't even have a voice necessarily to say what they want.

Because, for example, there are some people who simply don't have any language at all and who often have other associated issues such as intellectual disability or epilepsy.

And the parents and carers of those people absolutely do want a cure.

So I think the first thing to say is that there is a sort of spectrum.

I would also say that there may be people who might be interested.

If you've got a diagnosis, it's not that you want to be cured or have anything changed about you, you very much see it as part of your identity, but you might be interested to know a bit more about it.

And then finally, I think that there will also maybe be certain things that people wouldn't mind having a bit of help with.

So I think a nice example is people with ADHD, which actually co-occurs with autism quite a lot.

And some of the same genes are very likely implicated.

So if you have ADHD, you don't want your ADHD cured, you know, but you might well be happy to take some medications before you, a big big exam when you need to do a lot of revision.

So, you know, you might appreciate greater understanding and maybe people developing things that could be helpful without necessarily needing to talk about tears.

Well, thank you so much, Laura Andre, Professor of Developmental Neuroscience at King's College London, for taking us through that.

It's been a pleasure to have you on the programme.

Thank you very much.

And for a deeper dive on the real science of paracetamol use in pregnancy, do listen to our sister programme, Health Check, which is on the BBC World Service, and it's available on BBC Sounds now.

Now, Tim O'Brien joins me in the studio today, leading astrophysicist, our guide to all things space.

Hello, Tim.

Hello.

It's good to have you here.

We have to start with the first crewed mission to the moon in 50 years, planned as early as February next year.

Artemis, why now?

I think you could ask why has there been the big gap.

You know, why?

It's a pretty big gap.

Well, it's a pretty big gap from 1972 from the last time we were on the moon.

And I think probably that's a combination of two things, really.

One is

the advent of sort of private space exploration.

So, these private companies that have got involved in that, and that's sort of driven some of the competition, if you like, in space.

But also, the sort of political competition has reared its head again.

So, back in the days of Apollo, it was a competition between the USA and the Soviet Union.

And now we have other countries like China, India, and so on, all getting involved with missions to the moon.

And I think the USA has probably taken great note of that and wants to make sure sure that they are again leading that race if possible.

This is Artemis 2 set to launch as early as February next year.

What exactly will it do?

So, the intention is to send four astronauts in a capsule.

I would say that capsule is yet to be completed.

So, the earliest this mission could happen is the February date that was been talked about this week, so it could well be later than that.

But they send these four astronauts in a capsule around the far side of the moon.

So, they basically loop them around the far side of the moon, bring them back to Earth and splash down on Earth.

So that's the intention, is that just in many ways a replication of what Apollo did on a path towards landing people on the moon.

You've brought us some rather lovely audio from the Jodrell Bank archives, haven't you?

This is Sir Bernard Lovell in 1968 talking about the Apollo missions.

Let's just have a listen.

I think it's really one of the most exciting and habilest things I've ever heard in my life.

And it does indicate that here the human race has seized on this technological possibility.

I think the trouble is that so many people have tried to justify the enormous expense and the difficulty in terms of individual things like the scientific payoff, the spin-off, prestige, and so on.

I look on it more as

the human race being able to do something and still being willing to do it in spite of all the tremendous difficulties involved.

That's a wonderful clip.

I wonder how you reflect on what Sir Bernard Lovell says there, though, you know, about the scientific achievement and endeavour.

We've been here before, so how do these new missions to the moon, how does Artemis stack up in terms of what we can achieve?

People's ideas about the science and that might be achieved by going to the moon have evolved significantly, not least because we, you know, those Apollo missions brought back lunar rocks to be analysed.

So in terms of the sort of understanding of the origin of the solar system and the origin of our planet, then I think there's still big questions though that remain to be answered.

And that itself is a good reason.

Plus, the ideas involved in mining and minerals and so on that may be available on the moon.

Apollo 8, right?

That was Apollo 8.

That was Christmas 1968 when Sir Bernard was speaking there.

That was the first time that people had flown around the other side of the moon, which is what Artemis II is intended to do.

You know, one of the most memorable things about that mission, in fact, was,

you know, and Bill Anders was the Apollo 8 astronaut who took this amazing photograph, the photograph Earthrise, was the Earth rising over the limb of the Moon.

First time any human being had seen that.

And he sort of said, we came all the way to the moon, and yet the most significant thing we're seeing is our own home planet, the Earth.

In many ways,

it was thought to have sort of given a real impetus, a kickstart to the environmental movement.

It inspired the creation of Earth Day.

The sort of ugly connection that I would see here is that this story's come out in the same week that

the president of the USA referred, you know, frankly, ridiculously, to climate change as a con job at the United Nations.

And, you know, that would be laughable if it were if it weren't such a serious point.

It's interesting to look at the sort of political shifts from, you know, the Apollo missions inspiring that

regard for the protection of our planet and where we are now in terms of the political rhetoric.

Yeah, I think, you know, when you think about Apollo, it was driven by a political competition between these two systems of government, if you like.

But in the end, inspired this environmental awareness of the planet as this sort of fragile spaceship Earth floating in space that

we had to look after.

And now we're back into a political competition at some level with what's happening now with going back to the moon.

And I think we shouldn't forget that other key part of it, that looking at the Earth from space is crucial to our future.

And on that topic, we did have some potentially good news for our little blue dot this week.

The High Seas Treaty came into international law.

So that's a global treaty that paves the way for international waters to be placed into marine protection.

Inside Science went to Nice earlier this year ahead of the UN Oceans Conference.

So we've been following this quite closely and it is quite good news.

No, it is good news.

I I felt quite upset earlier this week with those sorts of announcements, but there's plenty of people who don't agree with that.

Yeah, the High Seas Treaty is an example of that, and I think you know, it will win out in the end.

Yeah, and you know, on this programme, we try and stick to what the scientific evidence is showing us.

On that topic, you have another

rather fascinating story about black holes.

We love a black hole on inside science.

Tell us more.

Yeah, I mean, I just thought, just in the last few weeks, some new results from

LIGO, so the Laser Interferometer Gravitational Wave Observatory,

which is two instruments in the USA, one's in Washington state and the other's in Louisiana.

And they basically measure ridiculously tiny sort of distortions in space-time, stretching and squashing of the instruments that result from ripples in space-time that are traveling through us all the time.

So less than a ten-thousandth the size of a proton is the change in size of the measuring, incredible technology.

And the first gravitational wave event they discovered was 10 years ago now from two black holes merging the brightest one the loudest one if you like with with the best data was this was discovered earlier this year and they've just published some results on that was because the signal to noise is so great on that observation so what you can see clues within that signal because the signal is so strong yeah exactly so what you what you get is this sort of you know these two black holes spiral around each other and gradually come closer and closer and closer called an in spiral And you sort of hear this as a note in this gravitational wave, like this ripple passing across the Earth.

And then as they finally collide, they make a single black hole.

And what's different about this one is the data is so good that you can see the black hole itself wobbling.

It's like hitting a bell, you know, if you strike a bell, the bell wobbles and it has various frequencies and it has harmonics of those and overtones.

You can see those in this data.

And by modeling those, you can start to test more details of general relativity.

And in fact, they've proved that one of Hawking's theorems, it's called the area theorem, which says that something about the event horizon area of a black hole has to increase.

It can never decrease.

They've been able to test that and show that's true in this case.

So everybody's sort of hopeful we'll prove Einstein wrong

at some point.

You know, that's what we're looking for, is a chink in Einstein's armor, I guess.

And from that, you open up a new, maybe a unified theory of physics.

Absolutely fascinating.

Well, Tim O'Brien, always a pleasure to talk to you about space.

Thank you so much for coming on Inside Science.

No problem.

Pleasure to be here.

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Today, on National Manufacturing Day, factories across the UK have thrown open their doors to the public and invited people to a behind-the-scenes look at the incredibly complex world of making the items we use, wear, and eat every day.

As part of our series of interviews with authors shortlisted for the coveted Royal Society Science Book Prize, we are speaking to a manufacturing guru, Professor Tim Minchell.

He is the first Dr.

John C.

Taylor Professor of Innovation and author of Your Life is Manufactured, a book that takes readers into the curiously secretive world of how things are made and the incredible journeys that products take before they end up in our hands.

Tim joins me now.

Welcome, Tim.

Hello, great to be here.

And you have told me to bring a prop with me for this interview, which I have here, a toilet roll.

Do explain.

Yeah, I know it's a little bit unusual this, but I thought this might be rather a nice example of why manufacturing really matters and why it's important that we understand it, even from very, very simple products, before we start talking about more complex products and bigger challenges.

There's certain physical characteristics required of toilet paper.

You want strength and softness.

And so to do that,

many,

if toilet paper is made from virgin wood, from new wood as opposed to recycled, you want fibers that have come from trees that have soft fibres, typically grown in in warm places, and fibers that are stronger, and those are typically grown from trees in colder places.

So, straight away, you've got trees which take decades to grow, grown in different parts of the world, that have to be chopped down, pulped up, made into wood pulp.

Then you take the water out from all this pulp, you ship it across the various oceans, you then put the water back in again and mix up into a composite material, you then spray it onto a whole series of very large heated rollers, you then form a whole series of mechanical

deformation activities onto that to give it the quilted texture you want and the strength you want.

And then you have to build up these plies of a typical toilet roll.

If something as simple as a roll of toilet paper has immense complexity behind it, what level of complexity is reflected in our cars and phones and everything else?

And your book really gets into that whole story, that whole global complex story of manufacturing.

Throughout history, factory design, the complexity of getting stuff around world from where it's made or grown and then made to who buys it.

Why did you want to really get under the skin of that and bring that to readers?

Well, it was partly a COVID-triggered story.

I think it was a shock for all of us, particularly in wealthier countries, to be confronted by empty shelves in the shops and to have that little message from the online retailers saying, not it'll be with you tomorrow, but it'll be a couple of weeks, a couple of months, unavailable.

I think this was a real shock that said, well, and then people were questioning, saying, well, why aren't these things arriving?

And if they're not arriving, why can't we just make them locally?

If it is a problem of personal protective equipment for the NHS, well, and it can't arrive from overseas, well, why don't we just make it locally?

So there's this sort of realization that we can still make things locally, but we haven't given it quite the attention it deserves.

And there are some problems with that.

That we don't anymore.

We don't do that sort of local manufacturing anymore.

It's become this really dispersed global system.

Exactly.

We certainly do do some local manufacturing.

but absolutely, there's this much, much more complex world than we had 50, 100, 200 years ago.

What is particularly problematic about that complexity?

It leads to a lack of resilience.

So when something goes wrong, we're in a complex system, you know, it's not that it's complicated, i.e.

there's lots of bits, it's complex, as in there are lots of bits and they're all interdependent.

So if one thing happens in one factory or one supplier or one mine far away, it has a knock-on effect all the way through the system.

And so a great illustration of what happens to a complex system with a point of weakness, you might recall this, the Suez Canal.

Ah, yes.

Yep, the ever-given getting wedged across the Suez Canal.

So that led to about 10-12% of global trade stopping dead in the water, literally.

They could not get the ships through the Suez Canal, and it took days to move it out.

And you thought, wow.

So if so much global trade of manufactured goods from different parts of the world goes through one narrow waterway and one person on one ship makes one decision to speed up slightly or slow down slightly, brings it all to a halt, that's not a resilient system.

And built into that, which you get into in your book, is the huge environmental cost of every part of this system in terms of manufacturing, how far things have to travel and waste as well.

How do we improve that?

If you boil all of manufacturing down to three words, it's about making, it's about moving, and it's about consuming.

And maybe the easiest one to focus on for sustainability is to say, we move stuff around an awful lot.

You know, the typical smartphone has traveled hundreds of thousands of miles, all the components being shipped to and fro around the world, many, many miles.

And every mile comes with

a bit of pollution associated with it.

So what we're trying to do is to say,

Well, is there a way of perhaps moving less?

And in some cases, you can, you can bring things closer to home, but there's a lot of good reasons why you don't do that.

But if you do need to move things, can we move them cleaner?

Which is why it's so exciting to see things like zero-emission ships being developed, reducing the impact of aircraft emissions, making more electric vehicles, not just cars, but electric trucks.

And of course, trains, an awful lot of them, are electric already.

So it's finding the best way of moving things around, if we have to move them, that's less harmful.

Well, thank you so much, Tim Minchell, who is also head of the Institute for Manufacturing at the University of Cambridge.

And good luck as well, because we will find out who the winner of the Royal Society Book Prize is next week.

Thank you very much.

If your curiosity has been piqued by Tim and you want to hear more secrets of science and technology, then you are just the person we want to hear from.

Have you got a burning science question?

If so, please email it to us at insidescience at bbc.co.uk.

No subject is too big, no discipline too small.

We're going to be assembling a top team of scientists to answer your questions for an upcoming episode, so do get involved.

Finally, it's been a busy programme, so let's have a few minutes of calm in nature.

On the glorious windswept Isle of Mull in Scotland, one conservationist has spent two decades protecting and monitoring the white-tailed and golden eagles that nest on the island.

This summer, he's been searching for one very unusual bird.

My name is Dave Sexton.

I was the RSVB's mull officer and I'm now an RSVB volunteer and ambassador.

And I'm sitting on the shore of beautiful Loch Nakiel on the Isle of Mull, looking out to Scarrisdale Rocks and actually watching a white-tailed sea eagle, probably hoping to steal a fish off an otter known as kleptoparasitism.

But I'm actually not here looking specifically for that adult eagle.

I'm looking for a...

a young eagle called Kinky.

Kinky is a remarkable young sea eagle.

In 2023 he suffered a really badly broken wing when his whole nest and tree came down in a summer storm and he couldn't fly.

And we lost sight of him.

He disappeared into the bracken and we assumed he'd died.

But the following spring we were out doing our surveys and suddenly heard this food begging call and in comes this young sea eagle with this huge bump on his left wing.

That was him.

had survived the winter.

The brake had fused and he was able to survive.

Not a great flyer, but not doing too badly considering.

And the parents that year put on hold their breeding attempt to look after him, which was just unprecedented in my experience.

So we then followed him through the summer and into the autumn, but then again as the storm started and the boats stopped, we lost track of him.

Earlier this spring, we set a challenge to visitors and locals to keep an eye out for Kinky.

And sure enough, back in July, I suddenly got a report that said he lives.

And there was his fantastic photograph.

And there he was soaring over the Isle of Aorsa, which I'm looking at right now, right out in the middle of Loch Nikil.

It was just the best feeling to know that he had survived his second winter, but this time probably on his own and coping really well.

I've been observing and studying and working with white-tailed eagles really since the first one I saw back 1980 and then worked with the RSPB on protecting the first nests and the first chick that fledged in 1985.

The project to reintroduce white-tailed eagles to Britain after they became extinct in 1918 began on the Isle of Rum just to the north of Mull in 1975 and we're celebrating that 50th anniversary this year.

So where is Kinky now?

Well we don't know and that's why I'm out here looking for him.

You know when I first saw the silhouette of the bird sitting out on the rocks here I immediately stopped and got the scope out but it is an adult it's not him.

Kinky is still only two years old so he's still in his immature plumage.

Kind of a very mottled brown but getting paler year by year until they end up with that pale head and and the full white tail.

But we think he's out there.

He's clearly surviving okay and I am hopeful because he doesn't have to be an expert hunter, I don't think, to survive with his wing injury.

He just has to be able to scavenge, which they do a lot of.

And he will be doing that, and I think he will survive.

I've just noticed this adult eagle was staring intently up into the ridge around Ben Moore, the highest peak on Mull.

And as I turn around to look, there are two young white-tailed eagles just clearing the ridge behind me.

It's not impossible one of them could be kinky, so I'm going to get the telescope on it.

Just when I alter the magnification and zoom in, looking at the flight profile on both of them, they look pretty normal, so it's not kinky, I'm afraid, on this occasion, but it could have been.

And one of these days, I'm going to be out here and I'm going to see him again, and that's going to be a very good day.

Wherever he is, we wish him well.

Thanks to Dave Sexton.

And that's all from me.

You've been listening to BBC Inside Science with Victoria Gill.

The producers were Ella Hubber, Tim Dodd, and Claire Salisbury.

Technical production was by Matt Chamberlain and Patrick Shaw.

The show was made in Cardiff by BBC Wales and West.

And if you want to test your climate change knowledge, head to bbc.co.uk, search for BBC Inside Science, and follow the links to the Open University to take the quiz.

The marvellous Marnie Chesterton will be with you next week, and I'll see you soon.

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