The sea whores. seahorse (Hippocampus) swimming Isolated on black. bluehand/Shutterstock.com A seahorse hovering mid water Joanne Weston/Shutterstock.com Pygmy seahorse Hippocampus bargibanti Dray van Beeck/Shutterstock.com Seahorse on reef FAUP/Shutterstock.com Thorny sea horse (Hippocampus histrix) scubaluna/Shutterstock.com pygmy seahorse - Hippocampus Colemani littlesam/Shutterstock.com pontohi pygmy seahorse Teguh Tirtaputra/Shutterstock.com Sea horses Vladimir Wrangel/Shutterstock.com Sea Horses Vladimir Wrangel/Shutterstock.com Seahorse Lovers Barbochi A Pygmy Seahorse on its host sea fan Jung Hsuan/Shutterstock.com Who "gives birth" doesn't matter in sex defining-were that true any male bird that sat on a nest would be gender swapped seeing how that's all the male's doing here(their woman-decides-the-babies matriarchy is cool though-wish humans had that ability). It's all about where the sperm and eggs start. It's especially true when considering incubating hundreds and hundreds of fries, which I would much rather call seafoals: seacolts&seafillies:)