1. Sex chromosomes

2. SRY gene

3. Sex determination Androgen insensitivity syndrome
Leads to ambiguous genitalia

4. Sex chromosome abnormalities

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

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

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

8. 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

9. 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

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

11. 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

12. 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