The genetics of Müllerian aplasia (absent fallopian tubes, absent or rudimentary uterine corpus and cervix, absent upper vagina) has never been investigated systematically. Some investigators believe the disorder is inherited in female-limited autosomal dominant fashion, males transmitting the mutant gene but, of course, not manifesting the trait. To investigate this possibility, we obtained pedigrees in 23 probands with Müllerian aplasia. None had an affected relative. The absence of affected individuals among 30 postpubertal sisters, 31 paternal aunts, and 40 maternal aunts makes it unlikely that a sex-limited autosomal dominant gene is a common cause of Müllerian aplasia in our population. Dominant genes might exist in other populations, and fresh dominant mutations cannot be excluded. However, polygenic/multifactorial inheritance is perhaps more plausible.