Prenatal diagnosis of 46,XX male fetuses,

Ultrasonography can accurately determine phenotypic sex differences from those of the genetic sex. Two cases were identified; they were the result of a translocation of the SRY gene from the Y chromosome to the X chromosome during meiosis. An ultrasonographic difference may represent an otherwise unsuspected genetic abnormality. (Am J Obstet Gynecol 1999;180:1006-7.)