Board Thread:Questions and Answers/@comment-39665740-20190605213457/@comment-43781716-20190910032256

Here's my theory, based on some observations from the manga and anime.

Every titan form, pure or otherwise, is male, with two exceptions. We've seen multiple times that even if the person is a woman, their titan is "male". Ymir (Jaw), Pieck (Cart) and Willy's sister (War Hammer) all have "male" titans, in that they don't have female parts. The two exceptions we've seen are Annie Leonhardt (Female) and Frieda Reiss (Founding). However, we've seen Ymir and Frieda's pure titans too. Ymir's is male — no surprise there. But so is Frieda's. Yes. Really. Feel free to check. So what does this mean? It means that Frieda went from having a male pure titan to getting a female type titan after inheriting the Founding Titan. Why? I think it's because she has royal blood. Because the descendants of Ymir are so closely linked to the Founding Titan, their titans take the shape of the holder. However, this doesn't apply to pure titans — Dina Fritz' pure titan was "male". So why is Annie's titan still female? The key is in the name: Female Titan, a name the Marleyan government gave it. I believe that regardless of the holder's gender, the Female Titan will always be female. And if I were the Marleyan government, why would I bother giving a permanently female titan to a man?

TLDR: Every titan is male except the Female Titan, which is always female, and the Founding Titan, which can change depending on the holder if they have royal blood. Otherwise, it's male (see Eren Yeager).