What boy animal gives birth?

This is a bit of a trick question! There are no boy animals that give birth.

Giving birth is a biological process specific to female animals.

Perhaps you're thinking of a seahorse? While they look like male and female, they don't actually have separate sexes in the way most animals do. The male seahorse actually carries the eggs and gives birth, but it's not a "boy" in the way we typically think of it.