Uhm I dunno if you read the comment above, his point was that certain differences do in fact correspond with gender, e.g. Rough and tumble play is more appropriate for most boys than it would be for the majority of girls. Do we have to prefix everything with NOT ALL to have a generally valid generalization?
To reply to the grandparent comment: I don't know if male and female children behave intrinsically differently, but this is going to be hard to measure in a society where everyone, including parents, are biased and subconsciously treat them differently based on their gender.