However I think the 'Friends' thing could have been better handled with modest tweaks. Why aren't there any boys/men in 'Friends'? What if boys want to play nurseries or tea parties.
When I was young the lego characters were mostly gender free but it seems increasingly that the 'boys' lego increasingly has male characters (even outside the branded Harry Potter/Lord of the Rings stuff). All the Firefighters and Police seem to be men when they could have been much more gender neutral (or mixed genders) without loss of fun to boys or girls.
You might think your child had no parental intervention, but parents are only one factor in enforcing gender roles. Are you sure you've kept them from watching TV, reading, and playing with other kids whose parents are not like you?
That's the key point. I've observed that ones tend to want one things and the others tend to want other things.
Of course there's cultural intervention, people do not live in bubbles, but it's much more subtle and, I believe, innate than what you think before having children (one data point: my daughter that I swore would never wear pink, actively prefers pink clothes, she wears other colors as well, but given a choice, usually chooses pink and from a really early age)
I meant kids will play with anything. Dolls, trucks, anything their hands can get ahold of. It's only once their parents or society starts subtly and not-so-subtly telling them they should be playing with these toys and not those toys do they start having a noticeable preference. Boys aren't hard-wired to like trucks and girls aren't hard-wired to like EZ Bake Ovens. That's all society.
My daughter preferred cars and trucks while young (under 4 years). She would cover the garage with blanket for the night, put her small truck to swing etc. The style of play was very different from the way that I saw boys playing with similar toys.
That said, I am still of the opinion that it is indeed mainly social, but that it is less social than one thinks it is, before.
I'd love to see some actual science about this, got any?
[0]: http://onlinelibrary.wiley.com/doi/10.1111/j.1540-4560.1990....
It's evident once you have some kids. I truly wanted that not to be the case, but reality bites.
For the PC crowd: This of course doesn't mean that girls will never play with robots or cars or that boys won't play with nurseries or tea parties. Of course a mix is healthy and should be encouraged. But the stereotypical preferences are truly marked in most cases, before parental intervention.