2%-6% of married women, and 1-3% of unmarried women were more or less exclusively homosexual. - Masturbation is common: about 62% of women, and about 92% of men have masturbated at least once. - How often they have sex: women reported to have had sex 2.8 times a week (in the late teens), 2.2 times a week by age 30, and once a week by age 50. - Sadomasochism: 12% of women, and 22% of men said they were sexually aroused by a sadomasochistic story. 55% of women, and 50% of men have had an erotic reaction when they were bitten. Criticism People said that the selection of the sample (those asked) was not well done. One in four were prisoners, and 5% were male prostitutes. The institute, or location Kinsey did these tests, then did another such tests, without asking prisoners or prostitutes, and the findings were more or less the same. People also say that child abuse may have been involved when collecting the data. Kinsey scale The Kinsey scale attempts to describe a person's sexual history or episodes of their sexual activity at a given time. It uses a scale from 0 to 6. 0 means the person tested is exclusively heterosexual. A person scoring 6 is exclusively homosexual. The Kinsey Reports are two scholarly books on human sexual behavior, Sexual Behavior in the Human Male (1948) and Sexual Behavior in the Human Female (1953), written by Alfred Kinsey, Wardell Pomeroy, Clyde Martin, and (for Sexual Behavior in the Human Female) Paul Gebhard and published by W.B. Saunders. Kinsey was a zoologist at Indiana University and the founder of the Kinsey Institute for Research in Sex, Gender, and Reproduction (more widely known as the Kinsey Institute). Jean Brown, Cornelia Christenson, Dorothy Collins, Hedwig Leser, and Eleanor Roehr were all acknowledged as research assistants on the book's title page. Alice Field was a sex researcher, criminologist, and social scientist in New York; as a research associate for Sexual Behavior in the Human Female, she provided assistance with legal questions. The sociological data underlying the analysis and conclusions found in Sexual Behavior in the Human Male was collected from approximately 5,300 men over a fifteen-year period. Sexual Behavior in the Human Female was based on personal interviews with approximately 6,000 women. In the latter, Kinsey analyzed data for the frequency with which women participate in various types of sexual activity and looked at how factors such as age, social-economic status, and religious adherence influence sexual behavior. The two best-selling books were immediately controversial, both within the scientific community and the general public, because they challenged conventional beliefs about sexuality and discussed subjects that had previously been taboo. The validity of Kinsey's methods were sometimes called into question. Despite this, Kinsey's work is considered pioneering and some of the best-known sex research of all time. Parts of the Kinsey Reports regarding diversity in sexual orientations are frequently used to support the common estimate of 10% for homosexuality in the general population. Instead of three categories (heterosexual, bisexual and homosexual), a seven-point Kinsey scale system was used. The reports also state that nearly 46% of the male subjects had "reacted" sexually to persons of both sexes in the course of their adult lives, and 37% had at least one homosexual Critics are justified in their objections that many of the most interesting and provocative statements in the [Kinsey 1948] book are not based on the data presented therein, and it is not made clear to the reader on what evidence the statements are based. Further, the conclusions drawn from data presented in the book are often stated by KPM [Kinsey, Pomeroy, and Martin] in much too bold and confident a manner. Taken cumulatively, these objections amount to saying that much of the writing in the book falls below the level of good scientific writing. In response, Paul Gebhard, Kinsey's close colleague, "Sexual Behavior in the Human Female" co-author, and successor as director of the Kinsey Institute for Sex Research, cleaned the Kinsey data of purported contaminants, removing, for example, all material derived from prison populations in the basic sample. (Gebhard had, while working with Kinsey, raised serious concerns about the use of prison populations especially, but had been shot down by Kinsey at the time.) In 1979, Gebhard (with Alan B. Johnson) published The Kinsey Data: Marginal Tabulations of the 1938–1963 Interviews Conducted by the Institute for Sex Research. Their conclusion, to Gebhard's surprise, was that none of Kinsey's original estimates were significantly affected by this bias: that is, the prison population and male prostitutes had the same statistical tendencies as the rest of the men Kinsey interviewed. The results were summarized by historian, playwright, and gay-rights activist Martin Duberman: "Instead of Kinsey's 37% (men who had at least one homosexual experience), Gebhard and Johnson came up with 36.4%; the 10% figure (men who were "more or less exclusively homosexual for at least three years between the ages of 16 and 55"), with prison inmates excluded, came to 9.9% for white, college-educated males and 12.7% for those with less education. Kinsey himself was extremely frustrated by the criticisms of his sampling procedures, because he maintained that there was no way to do a successful study about sex using random probability sampling. As Kinsey biographer Jonathan Gathorne-Hardy points out, because of the sensitive nature of a sex study, contacting a truly random sample will garner a very high refusal rate—as modern sex studies using random sampling have shown. If the study is trying to gather information about any sort of population subgroups, as Kinsey was, the small percentages of the population plus the high rates of refusal may make these subgroups effectively disappear, despite their importance to the study.