I have never pondered on this much but I see what you mean when you say girls are sort of trained at a young age (by the toys) that this is their role - playing house, making tea and taking care of their dolls - and most of the stuff comes in pink so now we can all be pretty sure these are the things girls play with -

I recall a friend (from my culture) wanted her kid (5 years old) wanted to learn some form of dance. The fact that there were mostly girls in the class did not bother him as he was looking forward to busting some moves - but her family discouraged her saying he would become all girly and it was not good for 'men' - what in the actual f*ck?!!