B.T.
I have a 3yr old son who loves playing with his sisters barbies, he will take them out of her room and into his. I was worried at first but i believe it is just his way of being more imaginative. the barbies are more realistic with there hair and clothes you can change, more so than his plastic super heros that dont do anything. I bought him boy dolls and he plays with those too. He pretends that he is the daddy and even tries to teach it to play ball. I wouldnt worry, hes little and i think you will notice as he gets older his preferences will change. At such a young age i dont think they can see gender difference in toys. Put him in a room with another little boy and i bet they would both be brushing the dolls hair.