Men with female karyotypes

: Hypotheses concerning phenotypic males with a female karyotype (46,XX males) are discussed. This peculiar chromosomal anomaly may be explained either by a mutation of autosomal sex determining genes or by a translocation of Y chromosomal genes to an X chromosome or an autosome. Recent studies concerning the H-Y antigen indicate that mosaicism with cell lines containing a Y chromosome may not be made responsible for phenotypic males with a 46,XX karyotype.