Crocodile was a woman – Myth & Fact

Myth: Ivankov knows a secret from Crocodile’s past, that nobody else knows, and Ivankov can change people’s gender, leading to speculation that Crocodile used to be a woman and had Ivankov change her to a him. In Episode 0 we only see the back of Crocodile’s head, suggesting that he was different back then and that Oda wants to keep it a secret for now.
Fact: So far, nothing has been confirmed. In the SBS for Volume 63 Oda drew the Shichibukai as children, and Crocodile appears to be depicted as a boy, although some have speculated that Crocodile could be a girl who dresses like a tomboy, but Oda has not yet stated anything one way or the other.