Surprising theory behind why boys are more likely to diagnosed with autism than girls

World-renowned researchers have detailed their theory on why it's widely believed that boys may be more likely than girls to be diagnosed with autism.

The British Medical Association stated that one in 100 children in the UK has a diagnosis of autism, with around 700,000 people being given the green light by medical staff during their lifetime.

The neurodevelopmental condition, which England Lioness Lucy Bronze, Elon Musk, and The Last of Us’ Bella Ramsay have all been diagnosed with, is considered a spectrum, meaning it affects individuals in different ways, as per the NHS.

According to the National Autistic Society, some people who are diagnosed may find socialising tiring; others may have intense interests or prefer that something is done in a very specific manner.

Research has previously suggested that boys are more likely to be diagnosed with autism spectrum disorder (ASD) in childhood than girls.

A newly-published paper claims that a girl's two X chromosomes could help 'buffer the effects of autism-associated mutations' (Getty Stock Image)

Now, experts from the Whitehead Institute for Biomedical Research believe they know why.

The Massachusetts research centre has claimed that a girl's second X chromosome, known as Xi, may play an active role in shaping gene expression across the genome, including many linked autism genes, as per the New York Post.

This theory, called the ‘female protective effect’, claims that girls can ‘buffer the effects of autism-associated mutations’ better than boys, thanks to having two X chromosomes, rather than one.

The hypothesis was outlined in research published by Maya Talukdar, Harvard-MIT MD-PhD student, and David C. Page, professor at the Massachusetts Institute of Technology, via the Nature Genetics journal on 30 March.

The experts, who aim to unify ‘epidemiological, genetic and mechanistic observations across autism and other male-biased congenital and developmental disorders’ with further research, suggest that if their theory is correct, then it could ‘reshape understanding’ of sex differences where autism is concerned.

Speaking about her paper, Talukdar said: “Many of the other congenital or developmental conditions we’re pointing to aren’t subject to diagnostic inequities in the way autism is.

Experts in Sweden have argued that the gender autism gap may not be as wide as first percieved in the country (Getty Stock Image)

“This strengthens the idea that the female protective effect is emerging from genetic differences in males and females.”

Following the publication, the pair plan to further explore Xi’s position as a ‘genetic suppressor of autosomal mutations in autism and beyond’.

Despite the theory that the inactive X chromosome acts as a female protector from autism, researchers from Sweden aren’t as convinced that there is still a male-female diagnosis gap in their country.

On 4 February, a paper was published by The BMJ that suggested autism may actually occur at comparable rates among Swedish male and female individuals.

The results showed that females ‘catch-up’ in adolescence, highlighting that an investigation into why ‘female individuals receive diagnoses later than male individuals’ is needed.

“These findings indicate that the male to female ratio for autism has decreased over time and with increasing age at diagnosis,” researchers wrote.

“This male to female ratio may therefore be substantially lower than previously thought, to the extent that, in Sweden, it may no longer be distinguishable by adulthood.”