Abstract
It is important for the Christian understanding of marriage that the couple should be man and woman, but what is the status of a postoperative transsexual? Against the thesis that someone who was unambiguously a member of one biological sex cannot then become a member of the other, two cases can be made. The psychological case argues that since biological sexuality cannot be considered on its own, the transsexual, by virtue of cross-gender identification, is properly understood as ambiguously sexed. The social case argues that public acceptance of a gender role, even in marriage, does not immediately depend on the "real" sex of the individual. Neither case is without difficulty.