I was there yesterday and wandered into the human biology section. Lots of sex, no gender, all good. Then I got to the bit on hormones and here I got confused.
It showed how XX and XY are the chromosomes and the baby gets one from each parent. There was a big pictorial flowchart on the wall showing how the genital ridge is formed a few weeks after conception. Then it said that at this point an XX genital ridge can turn into penis/testes and the XY genital ridge can turn into vulva etc.
It said if there were male sex hormones then the XX (or the XY)embryo would develop male characteristics and if there were no male sex hormones then the XX (or the XY) embryo would have female characteristics.
Scientists, what is this on about? The way the wall chart read (and it was covering an entire wall), irrespective of your chromosomes you could end up 'male' or 'female', it just depends on whether there are male sex hormones swilling around.
Are there really that many XX people wandering around with penises and testes? It honestly read to me from the wall as though it's pretty much 50/50 i.e. it's not your chromosomes that matter but the 'male sex hormones'.
Can someone explain this? My fear was that something very very rare is being presented as fairly common place, and I did rather wonder why that might be.
Thanks!