A SOX9 duplication and familial 46,XX developmental testicular disorder.

To the Editor: Female-to-male sex reversal in humans is rare, and when it is familial, it is extremely rare. We describe a family with a 46,XX testicular disorder of sex development in which three adult males (two brothers and a paternal uncle) were determined to be female according to karyotype (46,XX) and were negative for the SRY gene (Figure 1). The secondary sexual characteristics, behavior, growth and development, and skeletal development in these men were all normal male. Their general health and intelligence were normal. All three affected men were infertile with azoospermia. In two men, the testes were removed . . .