The main purpose of this legislation is to prevent the U.S. Secretary of State from issuing passports, passport cards, or Consular Reports of Birth Abroad that include an unspecified gender designation, specifically the "X" designation. The bill aims to establish clear gender categories for these documents, limiting them to only male and female options. Key provisions of the legislation include a requirement that all applications for passports and related documents must only allow for the selection of male or female as gender designations.