Hormones play a very important role
in determining the sexual behavior of an indiviual. There are two
groups of hormones: male hormones or androgens, like testosterone,
and female hormones like estrogen and progesterone. Hormones have
two general effects, which are organizing and activating
effects.
Organizing effects:
- Their organizing effect regulates
whether an embryo develops a male or a female phenotype.
- The organizing effects of sex
hormones begin very early in development, a few weeks after
conception, when the gonads develop into male testes or female
ovaries, depending on the presence or absence of testosterone and
its metabolic products.
- Organizing effects continue to
operate well after birth, perhaps even up to puberty.
- Example: influence atterns of
spatial reasoning: males likely to orient North and South
Activating
effects:
- It induces adult
sexual function and behavior around the time of puberty.
- They induce the secondary sex
characteristics that appear at puberty and the interest in sexual
activity after puberty by activating brain circuits previously
developed as part of the organizing effects of the presence or
absence of testosterone.
- Example: Menstrual cycle