When they need you to go to war, the US government acknowledges that a person can NOT change sex. pic.twitter.com/rWzwT9SnWV— Mimiof2 (@Mimiof28) October 10, 2022
US citizens or immigrants who are born male and changed their gender to female are still required to register. Individuals who are born female and changed their gender to male are not required to register according to the SSS website here.
OPM notes that “transgender” refers to people whose gender identity and/or expression is different from the sex assigned to them at birth (e.g. the sex listed on an original birth certificate). The OPM Guidance further explains that the term “transgender woman” is typically used to refer to someone who was assigned the male sex at birth but who identifies as a female. Likewise, OPM provides that the term “transgender man” typically is used to refer to someone who was assigned the female sex at birth but who identifies as male.