Sorry pipergirl, from what you've written, you disagree with me!!
I believe, as does Scroggs, that it's nature, not nuture.
I'm old enough (easily) to have an 18 year old son (as I mentioned above) and was at school and uni in early 80s. I found NO discrimination with girls and science (and I have a degree in Nuclear Physics). So either you are quite a bit older or went to a very backward-looking school!
When I was a child, my mother desperately wanted me to play with dolls and wear pretty dresses. Kicking and screaming was I if I had to wear a frock. I ignored my dolls; I wanted Lego and Meccano but my parents couldn't afford it. Apparently when I was 5, I asked my dad how a car worked. He used to work for Rootes (that'll take yer back eh Scroggs?) so explained it in terms of suck squeeze bang blow (no doubt he thought that was hysterical!).
That was nature, not nuture. I was (still am) a "not-very-common" case. I think an equilibrium will be reached though whereby all women who want to become pilots, can do so and those who don't, don't. Then we'll see the true picture. At best, I reckon it'll be around 10% or less.
Cheers
Whirls