market choices, accumulation of human capital, specialization within households, discrimination, and decisions about geographic location." More data are also needed to understand the degree of underrepresentation of sexual minorities in certain fields such as STEM, as well as the academic performance of sexual minorities more broadly. Kinsey Reports Two of the most famous studies of the demographics of human sexual orientation were Dr. Alfred Kinsey's Sexual Behavior in the Human Male (1948) and Sexual Behavior in the Human Female (1953). These studies used a seven-point spectrum to define sexual behavior, from 0 for completely heterosexual to 6 for completely homosexual. Kinsey concluded that a small percentage of the population were to one degree or another bisexual (falling on the scale from 1 to 5). He also reported that 37% of men in the U.S. had achieved orgasm through contact with another male after adolescence and 13% of women had achieved orgasm through contact with another woman. His results, however, have been disputed, especially in 1954 by a team consisting of John Tukey, Frederick Mosteller and William G. Cochran, who stated much of Kinsey's work was based on convenience samples rather than random samples, and thus would have been vulnerable to bias. Paul Gebhard, Kinsey's former colleague and successor as director of the Kinsey Institute for Sex Research, reviewed the Kinsey data and removed what he thought were its purported contaminants. He again found that almost exactly 37% of men had engaged in homosexual activity. However, he also pointed out that Kinsey later concluded it was a mistake trying to generalize to the entire population. More recent researchers believe that Kinsey overestimated the rate of same-sex attraction because of flaws in his sampling methods. See also Biology and sexual orientation Outline of LGBT topics (includes a categorisation of sexual orientations) Sexual diversity: explains the concepts of and differences between sexual orientation, sexual identity, and gender identity References Further reading Demographics Sexual orientation and science