The headline “Men who don’t find curvy women attractive ‘could father children with autism‘” sounds just too weird to pass up. I found it through Google alert on a rather curious blog “What Sorts of People.”

The entry does not comment on the title, just refers people to an article in the Daily Mail Reporter, published on January 8, 2009, with the same title as the blog entry.

A different blog, Feminist Philosophers, also mentioning the article, quotes

“Studies show that the waist-to-hip ratio of 70 per cent is what the majority of men find most attractive because it correlates strongly with good health and fertility”

and questions the “because.”

Knowing how the media have the tendency to distort the conclusions of scientific studies to make them more sensational (see, for example, the entry “Parental psychiatric disorders and children with autism“ from May 9, 2008), I went first to the actual press release, which is titled “Who we find attractive could have implications for the prevalence of autism, say researchers.”

I must say I agree with the Feminist Philosophers poster’s surprise at making an assumption that who we find attractive is strictly correlated to who we actually marry (or with whom we have children), which is what the authors of the study seem to imply. (Otherwise, they should have gone straight for assessing “the actual dimensions of parents of children with autism.”)

But I wanted more, so I found the actual article, published in the Journal of Autism and Developmental Disorders (J Autism Dev Disord) published by Springer.

The article, written by Drs Mark Brosnan and Ian Walker, both from the Department of Psychology at the University of Bath, is titled “A Preliminary Investigation into the Potential Role of Waist Hip Ratio (WHR) Preference within the Assortative Mating Hypothesis of Autistic Spectrum Disorders,” and was published in the January 2009 issue of the journal.

It is dense and somewhat tough to understand to a not-even-close-to-being-a-psychology-dr like me, but once I read it a couple of times I actually found it fascinating, because of a few points the authors raise that are not mentioned either in the Daily Mail article, or in the press release.

If I understand it correctly (and I must say I’m not sure I do), the whole point starts with assuming that there is a connection between testosterone levels in mothers and the fact that

“ASD affects somewhere between four and nine times as many males as females.”

because

“ASD’s male predominance has led to suggestions that autistic traits might be influenced by prenatal androgens, as prenatal testosterone exposure has been found to correlate with abilities associated with the triad of impairments.”

Here the article refers to three scientific articles examining androgens, fetal testosterone levels, and autistic traits.

(I had to look up what “androgens” means. Apparently androgens “stimulate or control the development and maintenance of masculine characteristics,” and the “most well-known androgen is testosterone.”)

So what I think the article says is that high or higher than typical levels of testosterone in a woman’s body while she’s pregnant might be one of the factors that could cause autism.

The second point is that

“testosterone levels in women are visibly signaled by waist-to-hip ratio (WHR: waist circumference divided by hip circumference) because testosterone causes the accumulation of fat cells around the waist.” (The typical range apparently is around 0.7-0.8.)

The hypothesis is then framed as follows

“[I]f some men were found to show a preference for higher-than-average-WHR mates, this would encourage greater prenatal testosterone exposure for these men’s offspring. Critically, if this preference were seen more than average in men with a genetic predisposition towards having children with ASD, this would make the incidence of ASD higher in a population than we would otherwise expect. Their genetic predisposition to ASD could potentially interact with the maternal genetic predisposition (passed from mother to child).”

Now, no matter how you look at it, to me statements like “a man attracted to higher-than-average waist-to-hip ratio women is likely to have a higher-than-average prenatal testosterone exposure for their offspring” do assume that the man in question will actually have “offspring” with that “higher-than-average WHR ratio” woman that he’s attracted to. I don’t think that’s necessarily true, but let’s say it is.

So what I think the researchers are saying is that just because you are a “boxy” (higher than average WHR) woman does not mean you will have a child with autism. But if you have children with a man who has a “broader autistic phenotype,” then the chance that your child with have autism is higher than average.

And now comes the interesting part, not mentioned in the Daily Mail or the press release – the “broader autistic phenotype” is apparently tied (if not equal) to a man’s “higher systemizing skills.”

Drs Brosnan and Walker refer to studies from a couple of years ago showing that

“fathers of children with ASD have been found to be overly represented within Science/Engineering disciplines”

and that there is an

“evidence associating children with autisms’ familiar over-representation in highly systemizing activities (such as engineering or mathematics).”

In plain words – the way I understand it – autism spectrum seems to run in families of engineers and other mathematically oriented professions.

(The article does not mention computer programmers or coders but I bet they are part of the group as well. I actually would expand it to include most academics overall; I’ve been working with academics for nearly fifteen years, I’ve seen some interesting “phenotypes” quite worthy of extended studies.)

That reminds me of the comment my son’s neuropsychologist made when I responded “it’s not the end of the world” when she confirmed the diagnosis of PDD-NOS – She said “Of course not! Just go and take a walk around the MIT campus!” (see the “Yes, it is PDD-NOS after all!” entry on May 2, 2008)

Laughing out loud, the Massachusetts Institute of Technology is probably one of the best places in the world to find a guy with “highly systemizing skills.” By the way, I went once to a ballroom dance class at MIT – it’s heaven for girls, they get to dance all the time, and it’s the guys who have to wait for a turn! (And no, it’s not where I met my husband, but he is good at systemizing. And no, I will not publicize my WHR.)

So again, a “boxy” woman will not necessarily have a child with autism just because she’s less curvy, and a scientist will not necessarily have a child with autism because he’s good at math, but if the two have children, then the chance that their first born male child will have autism is greater than average, especially if the guy was not a first-born himself.

(Oh, yeah – here are a couple more interesting nuggets not mentioned in the press release or the article – Apparently “engineers have relatively more sons than daughters.” Also, “the risk of ASD is higher in first-borns.” And there also seems to be a pattern “of children with ASD being firstborns to fathers who were not firstborn themselves.”)

What about “boxy” women who are scientists marrying their fellow scientist colleagues? I’m sure someone will study that soon (if they haven’t already).

And what I’d like to know is whether all women in the photographs used in the study, those with average WHR and those with higher than average, were equally well endowed in the “bosom department.” Yeah, I know guys look at the “WHR” but I think those measurements also play a big role (otherwise there wouldn’t be such a big market for implants). Although naturally big err.. cup size, probably has something to do with testosterone and estrogen levels as well, so in the end it probably doesn’t matter.