Author Question: Describe some of the evidence that genetic factors may influence sexual orientation. What will be ... (Read 97 times)

kshipps

  • Hero Member
  • *****
  • Posts: 571
Describe some of the evidence that genetic factors may influence sexual orientation.
 
  What will be an ideal response?

Question 2

Superior colliculus is to ____ as inferior colliculus is to ____.
 
  a. vision; hearing
  b. taste; smell
 c. vision; touch
 d. touch; hearing



annierak

  • Sr. Member
  • ****
  • Posts: 340
Answer to Question 1

Studies of the genetics of sexual orientation have focused mainly on twins. Early studies of the genetics of human sexual orientation began by advertising in gay or lesbian publications for homosexual people with twins. Then they contacted the other twin to fill out a questionnaire. The questionnaire included diverse items to conceal the fact that the real interest was sexual orientation. The results showed a stronger concordance for monozygotic than dizygotic twins. That is, if one twin is homosexual, the probability for the other to be homosexual is fairly high for a monozygotic twin, and less high for a dizygotic twin. However, the kind of person who answers an ad in a gay or lesbian magazine may not be representative of others. A later study examined the data from all the twins in Sweden between ages 20 and 47 . The Swedish study differed not only in the breadth of the sample, but also in the behavioral criterion. Instead of asking about sexual orientation, the researchers asked whether someone had ever had a same-sex partner. The results do not indicate number of people with homosexual activity or orientation. Rather, they indicate concordancethe probability of homosexual activity or orientation in one twin, given that the other twin had already indicated such activity. Although both sets of results show a higher concordance for monozygotic than dizygotic twins, there is huge difference between the studies. Other studies of twins in several countries also found higher concordance for sexual orientation in monozygotic than dizygotic twins, but the magnitude of the effect has varied considerably.

Several studies have looked for a particular gene that might be linked to sexual orientation, but they failed to find anything with a significant effect. Two studies reported a higher incidence of homosexuality among the maternal than paternal relatives of homosexual men. For example, uncles and cousins on the mother's side were more likely to be homosexual than uncles and cousins on the father's side. These results suggested a gene on the X chromosome, which a man necessarily receives from his mother. However, other studies have found no difference between relatives on the mother's and father's side and one study found more homosexual relatives on the father's side. Consequently, it seems unlikely that any gene on the X chromosome plays a major role.

Answer to Question 2

a



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

To combat osteoporosis, changes in lifestyle and diet are recommended. At-risk patients should include 1,200 to 1,500 mg of calcium daily either via dietary means or with supplements.

Did you know?

Eating carrots will improve your eyesight. Carrots are high in vitamin A (retinol), which is essential for good vision. It can also be found in milk, cheese, egg yolks, and liver.

Did you know?

The newest statin drug, rosuvastatin, has been called a superstatin because it appears to reduce LDL cholesterol to a greater degree than the other approved statin drugs.

Did you know?

A strange skin disease referred to as Morgellons has occurred in the southern United States and in California. Symptoms include slowly healing sores, joint pain, persistent fatigue, and a sensation of things crawling through the skin. Another symptom is strange-looking, threadlike extrusions coming out of the skin.

Did you know?

Though methadone is often used to treat dependency on other opioids, the drug itself can be abused. Crushing or snorting methadone can achieve the opiate "rush" desired by addicts. Improper use such as these can lead to a dangerous dependency on methadone. This drug now accounts for nearly one-third of opioid-related deaths.

For a complete list of videos, visit our video library