Module 53 REVIEW

• 53-1 How do sex hormones influence prenatal and adolescent sexual development, and what is an intersex condition?

• About 7 weeks after conception, a gene on the Y chromosome triggers the production of testosterone in males. This promotes male sex organ development.
• During the fourth and fifth prenatal months, sex hormones bathe the fetal brain. Different patterns develop as a result of the male’s greater testosterone and the female’s ovarian hormones. Prenatal exposure of females to unusually high levels of male hormones can dispose them to more male-typical activity interests later on.
• Another flood of hormones occurs in puberty, triggering a growth spurt, the development of primary and secondary sex characteristics, and the landmark events of spermarche and menarche.
• Intersex individuals are born with intermediate or unusual combinations of male and female chromosomes, hormones, and anatomy.

• 53-2 How can sexually transmitted infections be prevented?

• Safer sex practices help prevent sexually transmitted infections (STIs).
• Condoms, while offering limited protection against skin-to-skin STIs, are especially effective in preventing transmission of HIV, the virus that causes AIDS.
• Knowing one’s STI status and sharing it with one’s sexual partner is key to prevention.

• 53-3 What factors influence teenagers’ sexual behaviors and use of contraceptives?

• Sexual behaviors and attitudes vary from culture to culture and era to era.
• Factors contributing to teen pregnancy include minimal communication about birth control with parents, partners, and peers; impulsivity; alcohol use; and mass media influences.
• High intelligence, religious engagement, father presence, and participation in service learning programs have been predictors of teen sexual restraint.

• 53-4 What has research taught us about sexual orientation?

• Sexual orientation is an enduring sexual attraction, usually toward members of one’s own sex (homosexual orientation) or the other sex (heterosexual orientation). Variations include attraction toward both sexes (bisexual orientation).
• Today’s psychologists view sexual orientation as neither willfully chosen nor willfully changed.
• There is no evidence that environmental influences determine sexual orientation.
• Evidence for biological influences includes the presence of same-sex attraction in many animal species, straight-gay differences in body and brain characteristics, higher rates of homosexuality in certain families and in identical twins, the effect of exposure to certain hormones during critical periods of prenatal development, and the fraternal birth-order effect.

Multiple-Choice Questions

1. A child who is genetically female
   1. has received an X chromosome from her mother and a Y chromosome from her father.
   2. has received a Y chromosome only from her mother.
   3. has received a Y chromosome from her mother and an X chromosome from her father.
   4. has received two X chromosomes from her mother and none from her father.
   5. has received an X chromosome from her father and her mother.
2. Which of the following is a primary sex characteristic that changes at puberty?
   1. A growth spurt in height, especially for boys
   2. Development of breasts for girls
   3. Full development of external genitalia in both sexes
   4. Facial hair and deepened voice for boys
   5. Appearance of pubic and underarm hair in both sexes
3. Which of the following has been shown to be an effective intervention to reduce teen pregnancies?
   1. Abstinence-only sex education in schools
   2. Participation in service learning programs
   3. Increasing guilt related to sexual activity
   4. Taking a pledge to remain abstinent
   5. Increased exposure to sexual content in the media

Practice FRQs

1. Provide examples of a primary and a secondary sex characteristic for both males and females.

Answer

1 point: Male primary sex characteristics include growth of penis and testes and first ejaculation (spermarche). Page 546

1 point: Male secondary sex characteristics include body hair and lower voice. Page 546

1 point: Female primary sex characteristics include menarche and full development of external genitalia. Page 546

1 point: Female secondary sex characteristics include body hair, widening of the hips, and growth of breasts. Page 546

2. Explain evidence that suggests a genetic influence on sexual orientation from each of the following types of studies:
   • Family studies
   • Twin studies
   • Animal studies

(3 points)