By Susan Milius
Anybody who’s ever mused that the world would be better if men got pregnant needs to talk to Nico Michiels. And so does anybody who’s asked—or sung—”Why can’t a woman be more like a man?” Michiels has seen that world, or at least a version of it, and he’s even got pictures to show. It’s not pretty, he says.
Many snails, slugs, and worms are so-called internally fertilizing, simultaneous hermaphrodites. In any encounter, such creatures can deliver sperm, receive it for fertilizing eggs internally, or do both.