Biopsychology of Sex Behavior

1
Biopsychology of Sex Behavior

• Lecture 3 The Sexual Brain
• LeVay, Ch. 13

2
Chapter 13

• Gender identity is the subjective sense of ones
  own sex
• It may be tempting to think that ones gender
  identity results from experience of having male
  or female genitalia, reinforced by teaching
  other social pressures
• However, there may be a representation of ones
  sex in the brain whose development is at least
  partially independent of life experiences
• Transexuals are individuals who feel they are one
  sex even though phenotypically (biologically)
  they are another
• In childhood some are strongly gender-nonconformis
  t
• Diverse group
• No history of traumatizing experiences or mental
  illness
• Money Ehrhardt initially thought gender
  identity was more dependent on rearing. They
  described the case of a pair of identical
  twinsone of whom suffered an accidental
  destruction of the penis and the child was
  surgically reconstructed as a girl (and raised as
  a girl by her parents). There are reports that in
  adulthood, this individual never adopted a female
  gender identity
• 5-alpha-reductase deficiency rare congenital
  condition individuals with this condition are
  born with female-like external genitalia and are
  raised as girls. At puberty, breasts fail to
  develop, clitoris enlarges greatly to resemble a
  small penis, voice deepens, and body becomes more
  muscular.
• Imperato-McGinley found that skin cells in these
  individuals had defective enzyme
  5-alpha-reductase, which converts testosterone to
  dihydrotestosterone (DHT). And DHT plays a major
  role in masculinizing the external genitalia
• In spite of being raised as girls, these
  individuals adopt a male gender identity at
  puberty