In the oft-cited and oft-criticized Sexual Behavior in the Human Male (1948) and Sexual Behavior in the Human Female (1953), by Alfred C. Kinsey et al., people were asked to rate themselves on a scale from completely heterosexual to completely homosexual. Kinsey reported that when the individuals' behavior as well as their identity are analyzed, most people appeared to be at least somewhat bisexual — i.e., most people have some attraction to either sex, although usually one sex is preferred. According to Kinsey, only a minority (5–10%) can be considered fully heterosexual or homosexual.[citation needed] Conversely, only an even smaller minority can be considered fully bisexual (with an equal attraction to both sexes). Kinsey's methods have been criticized as flawed, particularly with regard to the randomness of his sample population, which included prison inmates, male prostitutes and those who willingly participated in discussion of previously taboo sexual topics. Nevertheless, Paul Gebhard, subsequent director of the Kinsey Institute for Sex Research, reexamined the data in the Kinsey Reports and concluded that removing the prison inmates and prostitutes barely affected the results.