If Fetus is XY --> TDI --> Testes

If Fetus is XX --> No TDI --> Ovaries

Formation of Internal Sex Organs

Seminal Vesicles, Vas Deferens, Prostate

Testes-- --> MIF -----------------> Atrophy of Mullarian Ducts

Females: Ovaries --> No Testosterone ---> Wolffian Ducts Atrophy

Ovaries --> No MIF -------------> Mullarian Ducts Develop into the

Uterus, Vagina, Fallopian Tubes

Formation of External Sex Organs

Males: Testosterone -----------> Penis, Urethra, Scrotum

Females: No Testosterone ------> Clitoris and External Labia

XO Turner's Syndrome

Males produce testosterone, but it can’t masculinize the body

Males have fully female body and brain, raised as females

Congenital Adrenal Hyperplasia (CAH) - XX Chromosomal Abnormality

Adrenal Cortex produces extraordinary amounts of adrenal androgens

In genetic females, extreme genital and behavioral masculinization

Androgen-Induced or Pseudohermaphroditism

Males: LH, FSH --> Testes --> Testosterone --> Secondary Sexual Characteristics

Females: LH, FSH --> Ovaries --> Estrogens ----> Secondary Sexual Characteristics

Differences between the sexes are not limited to sex organs or secondary sexual characteristics. Hormones also have organizational effects on brain circuitry during critical periods.

Pre-Optic Area of the Hypothalamus

Bulbocavernosus Nucleus of the Spinal Cord

Cerebral Cortex

Corpus Callosum

Laterality of the Two Cerebral Hemispheres