Sex chromosomes

SRY gene

Sex determination Androgen insensitivity syndrome Leads to ambiguous genitalia

Sex chromosome abnormalities

Klinefelter's syndrone XXY male Infertile or reduced fertility Gynecomastia (breast development) Late development (mental and physical)

Turner's syndrome X0 (“X-null”) female Infertility Swollen hands and feet Wide, webbed neck Incomplete puberty No periods

Congenital Adrenal Hypoplasia XX females have prenatally high levels of male hormones resulting in varying degrees of external male genitalia

Androgen insensitivity syndrome XY chromosomes SRY gene produces testes Testes release testosterone, but the hormone has little or no effect Can be complete or incomplete

Intersex Both CAH and incomplete AIS can lead to ambiguous genitalia e.g. partial closing of the outer labia, an enlarged clitoris, and a short vagina

Gender dysphoria A condition in which a person feels that there is a mismatch between their biological sex and their gender identity

Body map A strip of cortex holds a complete (though distorted) body map If a body part is amputated it may be experienced as a “phantom limb” because the brain is not altered

Phantom penis Experienced by 2/3 of men who lose theirs in an accident Experienced by 1/3 of MTF transsexuals, following surgery Experieneced by 2/3 FTM transsexuals, from childhood