Laumann embarked on an unprecedented study of America's sex life. Chapter 7 outlines sex practices and preferences, chapter 8 presents survey results on masturbation and erotica. The book also has two appendices, which provide a graphic representation of the survey respondents and the sex questionnaire which was used. Or scientific words to that effect. Knowing the reasons for various behaviors allows people to decide whether or not they want to change their own behavior, and, if so, what might make such change possible. In the fifth chapter, the question of how many sex partners Americans have is explored. After an introductory chapter on sex in America, the book proceeds with a chapter describing the survey used to gain the data. Gagnon, and Edward O. More people become sexually active at an earlier age, marry later, and are likely to divorce these days; therefore these sexually active citizens are likelier to have more sexual partners in one lifetime. When we marry, we tend to be with people like ourselves. In , highly regarded social scientists Robert T. According to Sex in America, the epidemic does not appear to be spreading widely to the heterosexual population but remains concentrated among homosexual men, intravenous-drug users, and their sexual partners.