In the ways of the childless person who thinks she knows all, before I had children I would have argued that there's not much difference between boys and girls. Surely nurture trumps nature in the types of toys children were drawn to or how they liked to spend their time.
Having three sons shocked that notion right out of me. I am fortunate to have three young renaissance men. They all love to read, sing, and attend theater, but each boy has his own testosterone-driven interests: Chris--WWE wrestling (blech!) and video games, Kieran--sword fighting and battles between good and evil, and Nick--Thomas the Tank Engine, fire trucks, and cars. None of them seem particularly drawn to sports, although there is still hope for Nick. Swimming, rather than team sports, suits them just fine.
The two big gender differences I notice are ENERGY and NOISE. Not that some girls are not as energetic and noisy as boys, but in general this is the biggest difference I have observed.
A new study has found that children as young as 9 months old make stereotypical gender choices when selecting a toy. They haven't ruled out the influence of nurture in these choices (other studies have found that immediately out of the womb, girl babies are treated differently than boy babies). But whereas earlier in my life I might have suspected that nature was not as big of a factor, now I'm not so convinced.
All I can say is thank God I don't have one of those boys who makes guns out of bananas. We've got to take credit for something--maybe that's our nurture. Or maybe it's genetics.