Answer to Question 1
Cultural influences affect what people are told about sexual behavior, as well as what they experience and observe around them. Variations in the age of sexual intercourse, gender roles, and types of behaviors judged acceptable are all functions of cultural values. For example, researchers know that in Papua New Guinea, young boys engage in homosexual oral sex with teenage boys and avoid masturbation because it is believed that semen is crucial for male development. In Western cultures, attitudes toward premarital sex and use of contraception vary.
Answer to Question 2
Homosexuality appears to run in families, with concordance rates for homosexuality more common among identical twins than fraternal twins or siblings. Other evidence suggests that homosexuality is associated with differential exposure to hormones in utero. Research also suggests that the structure of the brain may differ in homosexuals. However, temperamental factors may also interact with environmental factors to produce sexual orientation. Bem (1996) argues that those things that seem exotic tend to become erotic. In support of environmental influences, even identical twins don't always have the same sexual orientation, and boys with an increased number of older brothers are more likely to be gay.
The sexual cycle of flowering plants involves alternation of sporophyte and gametophyte generations.
Bacterial Culture
Bloodstained evidence.
The Global Reach of Latino Culture
Cultural Coherence and Diversity
Cross-section through a Femur