Why do they need to be categorised thus, though, Helpmeout? Why not categorise them, as a pp suggested, by design (seaside, flowers, animals, transport) and parents will choose the one their child will like best? I assume most parents will choose based on what their child will like, not on what most children of their child's gender will choose.
Unless something actually requires a penis, or a vagina, to facilitate its use, it doesn't need to be categorised as for boys or for girls, IMO.