In some areas of clinical medicine, discussions about fertility preservation are routine, such as in the treatment of children and adolescents facing cancer treatments that will destroy their ability to produce gametes of their own. Certain professional organizations now offer guidelines for people who wish to modify their bodies and appearance in regard to sex traits, and these guidelines extend to recommendations about fertility preservation. Since the removal of testicles or ovaries will destroy the ability to have genetically related children later on, it is imperative to counsel transgender people seeking body modifications about fertility preservation options. Fertility preservation with transgender people will, however, lead to unconventional outcomes. If transgender men and women use their ova and sperm, respectively, to have children, they will function as a mother or father in a gametic sense but will function in socially reversed parental identities. There is nothing, however, about fertility preservation with transgender men and women that is objectionable in its motives, practices, or outcomes that would justify closing off these options. In any case, novel reproductive technologies may extend this kind of role reversal in principle to all people, if sperm and ova can be derived from all human beings regardless of sex, as has happened with certain laboratory animals.