Male monkeys prefer boys' toys.

The New Scientist reports that:

It's thought of as a sexual stereotype: boys tend to play with toy cars and diggers, while girls like dolls. But male monkeys, suggests research, are no different (see a related video report).

This could mean that males, whether human or monkey, have a biological predisposition to certain toys, says Kim Wallen, a psychologist at Yerkes National Primate Research Center in Atlanta, Georgia.

Wallen's team looked at 11 male and 23 female rhesus monkeys. In general the males preferred to play with wheeled toys, such as dumper trucks, over plush dolls, while female monkeys played with both kinds of toys.

This conclusion may upset those psychologists who insist that sex differences – for example the tendency of boys to favour toy soldiers and girls to prefer dolls – depend on social factors, not innate differences.

Before I became a mother I would have been shocked by this headline, but ever since my children were around 2 years old I have realized that genders do have different preferences. When Ben and Shira were tiny, I was true to every lesson I learned at university wrt gender stereotyping. I even handedly gave both children dolls, dump trucks and stuffed toys. I watched with bemusement when Ben piled his dolls and stuffed animals into his dump truck and sent them careening down the cliff that was the stair. Shira took the same dump truck, dolls and stuffed animals and turned the dump truck into a bed for the dolls and animals and then proceeded to sing them to sleep.

They both played with a Thomas the Tank Engine train set. Shira would divide the trains into families and play loving families with them. Ben would have them in conflict situations or have them doing heavy work.

I've only seen more and more examples of how the genders differ and I've given up on trying to be even handed wrt gender stereotyping. I empower both children to be the best they can be but I don't insist that Shira be more aggressive or that Ben be more passive. They are what they are and their genetics probably play a fairly large role in that.