A possible etiology of the infertile 46XX male subject.

We report on an infertile male patient with the predominant 46XX female karyotype. A testicular biopsy revealed widely separated testicular tubules, absence of sperm formation and large numbers of Leydig cells. Chromosome studies, including measurements of the X chromosomes, showed a significant difference between the lengths of the short arm of the 2 X chromosomes. This information lends support for an X-Y chromosome interchange as the etiology of this syndrome. The clinical features of this rare syndrome and other theories of etiology of XX male subjects are discussed.