On the gendered toys thing, Rhesus monkeys show gender preferences for different types of toys. I'd be surprised but interested to see a follow-up paper about cross-species gender expectations forcing toy choices.
This study was done on adult monkeys. And AFAIK, in humans the differences in neural connectivity are negligible until testosterone kicks in. On the other hand, in adults, gender differences are drastic.
> And AFAIK, in humans the differences in neural connectivity are negligible until testosterone kicks in.
Possibly, I'm not a biologist, but the 4th paragraph of the intro is interesting in that regard:
"Prenatal hormone exposure is known to influence children’s toy preferences as girls with congenital adrenal hyperplasia (CAH), an inherited enzymatic defect....show more boy-typical toy preferences than do their unaffected sisters or control girls....This preference is evident in CAH girls who look like and are reared as girls ... and despite the fact that most of these girls have typical female gender identity... When parental socialization was explicitly studied, one study found that CAH girls are more strongly encouraged to play with female-typical toys than are unaffected female siblings, yet they still show a masculine toy preference.... Thus toy preferences appear sensitive to prenatal androgen exposure..."
You are right. My bad. I've only briefly looked to confirm that the study was not specifically targeting juvenile monkeys. But in fact 52% (8+10)/(11+23) of monkeys were juvenile. Still, half are post puberty and taking into account "females reach puberty around age three while males are sexually mature by age four" (Rawlins & Kessler 1986, that probably diminishes this 52%. And as per the study itself "Overall sample size precluded analysis of individual age groups." So, I still wouldn't be too happy to transfer that results into human children domain.
paper: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2583786/
bbc news article w/ video: http://www.bbc.com/news/science-environment-29418230