Testicular feminization is a disorder of the androgen receptor. Phenotypically, the patient appears female, but has a blindly ending vagina and lacks a uterus or other female internal reproductive organs. The patient has an XY genotype. Since the gene for testes determining factor (TDF) is on the Y chromosome, TDF will cause the indifferent gonad to develop into a testis containing Seoli cells. Seoli cells at this stage will secrete MIF, a substance that suppresses the paramesonephric ducts, preventing the formation of female internal reproductive organs. This patient would not have a streak ovary, a finding in Turner's syndrome that is associated with a 45,XO genotype. In fact, the patient would have testes, since the genetic complement contained a Y chromosome. The testes in individuals with testicular feminization syndrome are often undescended and are usually removed surgically. This patient would not possess a uterus or an oviduct. Both of these structures are derived from the paramesonephric duct, which is suppressed by MIF.