This article deals with the legal status of postoperative transsexuals in terms of marriage and sex-based classifications. Until recently, sex has been assumed to be binary, i.e., male and female. Whether sex is immutable or transitory, objective or subjective, has now become an international concern. This article addresses every case in the world every decided on this issue. The resolution is centrally important to the battle over marriage and sex0based classifications. The thesis of this article is that sex is an immutable characteristic at the time of birth and must be determined by objective criteria. Sex must be determined by objective factors such as biology and physiology. A person’s sex is determined by chromosomes. When there is harmony between biology and physiology, surgery cannot alter a person’s sex merely because that person desires a different gender. If sex is primarily a state of mind and based on subjective mental desires, equal protection for sex-based classifications becomes meaningless. To maintain any stability and meaning to sex-based classification, sex must (and can) be determined by objective factors
