I have children of both sexes and so it was easy for my boy to play with dolls etc. It's not a problem. My friend who has 3 boys did buy a doll etc for one of her boys as he really liked them. It encourages caring etc... all things his future wife will thank you for!!!!!
My friends boy is now a football mad 7 year old.... a typical boy.
I know Dad's often have problem with it... but it won't be damaging to him to have a doll....In fact it'll probably do him good.