I just remembered men between 18 and 26 have to register with Selective Services. Does anyone know how this applies to transmen? According to the website, you can be denied benefits or a job if you're late.

You would still need to register. But since they dont allow tgs in the military, they most likely never take if they ever reinitialized the draft.

Only if your legal gender is male.  for me, when I got the letter to change my legal gender, I went to the DVM to get my new drivers license made.  and they asked me right then and there if I would like to sign up for the selective service. I said yes. and a few weeks later I got my registration card in the mail.

Like JohnAlex said, only if you're legally male, and it's really easy to if you're getting a new license at the DMV. That's what I did. And of course, they can't take you because you're trans.

How old are you? If you are legally male and over the age limit, you have to apply for a letter that says that you weren't required to register.

I'm old enough to get this done, and my driver's licence says male but only by happy mistake. I suppose I could go ask them to sign me up at the DMV...

Are you legally male with the federal government, though?

Anyway, it certainly can't hurt to register, or try to register. Worst case, they send you a letter and tell you that you didn't need to.