One of the issues that autistic people face is the idea that autism is an “epidemic” occurring at higher and higher rates as time moves forward. While it is true that the number of diagnostic referrals (and diagnoses themselves) is increasing quite dramatically, the idea that autism is an epidemic is incredible harmful. It highlights the societal belied that autism is some kind of disease that poses a threat rather than being a natural variation in the human brain. In this article I hope to answer the question as to whether this is a fair analysis.
Genetic factors for autism
To understand the genetic factors around autism, I first bring to your attention studies conducted on twins. Frazier et al (2014) looked at heritability and environmental factors surrounding Autistic twins. They found that monozygotic (identical) twins were likely to both be Autistic, twice as like as dizygotic (non-identical) twins. This suggests that there is a strong genetic factor in the emergence of autism rather than environmental factors taking precedence. To summarise, it is likely that autism is inherited genetically rather than being something triggered by variable in the external environment.
What are the heritability rates for autism?
To consider the likelihood of autism being inherited, I considered another twin study by Tick et al (2016). This study found extremely high heritability, with their estimates being 64%-91%. Supporting this is Sandin et al (2017) which found a heritability rate of 84%. To consider this is simple terms, it is extremely likely for autistic parents to have autistic children. In fact, most of the children birthed by Autistic parents will themselves be Autistic.
How many Autistic people are there in the UK?
I recently wrote an article that cited studies finding that there were over 450,000 diagnosed Autistic people in the UK. This research went on to estimate that there could be as many as 1.197 million undiagnosed Autistic people in the UK. Taking both of those figures into account, we can infer that there are around 1.5 million Autistic people living in the UK, both diagnosed and undiagnosed. There is limited data around how many Autistic people are having children, but the existence of charities such as Autistic Parents UK implies that this is a significant aspect of Autistic experience. In the absence of better data, I will assume that Autistic people are having children at roughly the same rate as non-Autistic people.
What is the average number of children per family in the UK?
This website suggests that on average there are 1.74 children per family, with the Office for National Statistics finding that 42% of families have one or more dependent children, equating to some 8.2 million families. Suggesting that in the UK there are around 14.268 million children in the UK. With the ONS finding that there are 19.4 million families in the UK, and knowing that the statistics here only look at dependent children, the 1.74 figure can be inferred to be relatively accurate.
Autism is increasing because Autistic people are reproducing. Even if only half of 1.5 million(ish) Autistic people in the UK had children, on average that would produce almost another 1.3 million Autistic people if the heritability rates are accurate. I believe that the way towards tackling the “epidemic” argument and removing stigma from Autistic lives is to do robust research into Autistic families. We are not a disease or an epidemic, we are humans. Like any other human, many of us will go on to have families of varying sizes. Given this, we can not be surprised that the number of Autistic people is increasing. It’s time the world caught up with us and supported us, rather than empower the people who seek to eradicate us.