A person with a penis is a person with a penis, no matter what they think they are.
From the Dr. Seuss book "Horton Hates His Willie", right?
Correction: A person with a Y chromosome is a person with a Y chromosome, no matter what they think they are. If you cut off the penis of a person with a Y chromosome, you have a physically mutilated person with a Y chromosome. And if you give hormone injections to the same person, you have a mutilated person with a Y chromosome and a severe hormone imbalance.
People have been drawing the needed symbols on bathroom walls for decades. Instead, put them on the door, look in your pants and go to the one that matches. Problem solved!
Having a Y chromosome is the telling fact, you can remove the appendage.