Is the seahorse the only animal whose male carries the offspring through gestation?

Does the penguin male incubating an egg count?

It’s seahorses, leafy sea dragons, and pipefish; members of the Syngnathidae family: http://en.wikipedia.org/wiki/Syngnathidae

@DominicX OK, right…but any other species besides?

I’m pretty sure Syngnathidae is the only group of animals that does this. I don’t think there are any other animals that have “male pregnancies”.

In some species of frogs, I believe the males carry the eggs until they hatch.

Midwife toads and some other amphibians, and quite a few species of mouthbrooding fish. Among birds, phalaropes. After gestation, marmosets and tamarins turn all baby care except nursing over to the males.