system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 why the male seahorse gives birth.

What is it that makes the male seahorse male? Why do we labeled them male if they give birth?
gpt
Male seahorses have a pouch that they use to receive a female seahorse's eggs.  After receiving the eggs they supply sperm to fertilize the eggs.  It's counter to how other species function but they are labeled as male because they supply the sperm not the eggs.