[Female karyotype and male phenotype: XX men. Apropos of 2 cases].

Males with a female karyotype are of special interest because they bear potential information on male determining factors leading to a masculine development in spite of a normal female chromosome constitution. We present 2 XX males, the clinical features correspond closely to many of those described in De La Chapelle's series of 46,XX males: reduced body height, infertility with small testicles, marked seminiferous tubular atrophy and azoospermia, slightly decreased testosterone level in serum and increased FSH and LH levels. Four main classes of theories concerning the etiology of XX males are presented, while mosaicism appears very unlikely in most cases, autosomal gene mutation, deletion or inactivation of X-chromosomal genes, X-Y interchange remain possible. The etiology of XX maleness may well be heterogeneous.