A purified antibody or an antigen binding fragment thereof is provided that binds selectively to a protein specific to an X chromosome of a mammalian sperm cell. The sperm cell protein comprises an amino acid sequence set forth in SEQ ID NOs: 4 and 9 16. The antibody or antigen binding fragment thereof may be derived by immunization of a host by an antigenic peptide composition comprising one or more natural or synthetic antigenic peptide sequences set forth as SEQ ID NO: 1 SEQ ID NO: 2 SEQ ID NO: 3 and SEQ ID NOs: 4 and 9 16. The antibody finds utility in identifying an X chromosome bearing sperm cell population and in methods for skewing a sex ratio in mammals.
