ch. 10.2. Variation in sexual behaviour Flashcards
What evolutionary advantage is suggested for why women are more interested in men’s wealth and success than men are interested in women’s wealth?
During pregnancy and early child care, a female is limited in her ability to get food and therefore prefers a male partner who can provide for her. A healthy male is not similarly dependent on a female.
What is a common cause for a genetic female (XX) to
develop a partly masculinized anatomy?
If a genetic female is genetically deficient in her ability to produce cortisol, the pituitary gland does not receive negative feedback signals and therefore continues stimu- lating the adrenal gland. The adrenal gland then produces large amounts of its other hormones, including testosterone, which masculinizes development.
If a genetic female is exposed to extra testosterone during prenatal development, what behavioral effect is likely?
A girl who is exposed to extra testosterone during prenatal development is more likely than most other girls to prefer boy-typical activities.
What would cause a genetic male (XY) to develop a partly feminized external anatomy?
A genetic male with a gene that prevents testosterone from binding to its receptors will develop an appearance that partly
or completely resembles a female.
When children who had been reared as girls reached puberty and grew a penis and scrotum, what happened to their gen- der identity?
Most changed their gender identity from female to male.
For which kind of twin pair is the concordance for sexual orientation greatest?
Monozygotic twins have higher concordance than dizy- gotic twins. Be sure to state this point correctly: Do not say that homosexuality is more common in monozygotic than dizygotic twins. It is the concordance that is greater—that is, the probability that both twins have the same sexual orien- tation.
It seems difficult to explain how a gene could remain at a moderately high frequency in the population if most men with the gene do not reproduce. How would the hypothesis about epigenetics help with the explanation?
According to this hypothesis, some unidentified event in the environment can attach an acetyl group or a methyl group to some gene, increasing or decreasing its activity. That gene modification could be passed to the next generation, producing evidence for a hereditary effect, even though there is no “gene for homosexuality.”
If events like this happen often enough, the result could be a moderately high prevalence of homosexuality, even if men with the inactivated gene seldom reproduce.
By what route might having an older brother increase the probability of male homosexuality?
Having an older brother might increase the prob- ability of male homosexuality by altering the mother’s immune system in the prenatal environment. The effect of the older brother does not depend on growing up in the same home.
How might stress to a pregnant rat alter the sexual orienta- tion of her male offspring?
Evidently, the stress increases the release of endorphins in the hypothalamus, and very high endorphin levels can block the
effects of testosterone.
In LeVay’s study, what evidence argues against the idea that INAH-3 volume depends on AIDS rather than sexual orientation?
In his study, the average size of INAH-3 was about the same for heterosexual men who died of AIDS and those who died of other causes. One homosexual man who died of other causes had about the same size
INAH-3 as homosexual men who died of AIDS
What is meant by the term “sexual selection”?
Evolution favors characteristics that make an indi- vidual more appealing to the opposite sex.
Congenital adrenal hypertrophy results from a genetic disability to produce normal amounts of which hormone?
cortisol
What causes testicular feminization, in which a genetic male looks female?
Lack of receptors for testosterone
The conclusion that sexual orientation is partly heritable depends mainly on what evidence?
Comparisons of monozygotic and dizygotic twins
