Twin gender roles

Firstly, I love how as soon as Zach leaves the country this blog comes to a complete halt. Aren’t we doing anything interesting this summer???

Secondably, I was watching CNN earlier (while working out – YAY ME) and need to vent about a story I heard/watched. There’s apparently some study looking at twins where one is male and the other is female. They claim that the female twin ends up being more masculine than non-twin girls because (supposedly) she spent 10 months in the womb next to her twin brother and his male-making hormones.

Problems with this: 1) there’s no control for the masculine behaviors being due to how the twins were brought up, 2) this assumes gender is related to sex, 3) assumes that there are two genders, 4) assumes those two genders have specific behaviors associated with them. The news anchors described the “practical application” of this project as follows: girls with twin brothers are apparently less likely to suffer from an eating disorder, so (according to the anchors, not any scientists) perhaps they can use this knowledge to prevent non-twin girls from getting eating disorders. WHAT?! If the eating disorder thing is even true (since there were no facts like how many twin pairs were looked at and how many “most” is), and if it is due to being twins (i.e. stuff that happens in the womb) and not due to how they were raised, what are they going to do? Add more testosterone to the womb when they know it’s a girl?? That was like the WORST example of a practical application I’ve ever heard.

One interesting “fact” about this story: Apparently girls with twin brothers have more skeletally male skulls (big teeth is the thing mentioned by the news anchors). I would be interested to know the clinical results on this topic. Is there a significant difference between twins with brothers and other girls? Is this enough of a difference that we could tell if a girl had a twin brother based on skull? I’m guessing probably not – trends like this are rarely applicable, but that was the part of this story I found interesting.

My own personal understanding of sex and gender is that what a person does, what a person likes, is usually due more to environment than genes and hormones and such. Notice I said “due more” not “due entirely” – a very smart populations genetics professor once told me that nature and nurture are necessarily affected, and I believe him. But I think it’s crap to assign certain behaviors to males and others to females!

And this is part of why I try not to watch my news – I save TV for good stuff like Food Network!