On January 5, 1948, Alfred Kinsey’s Sexual Behavior in the American Male was published, much to the delight of voyeurs, sociologists, and joke writers. The book had impeccable scholarly credentials: Its author was an Indiana University biologist and its publisher was W. B. Saunders, a respected company specializing in medical texts. Because of the book’s expected popular appeal, Saunders had ordered twenty-five thousand copies instead of its usual two or three thousand. They instantly disappeared from the shelves, and soon two printers were working around the clock to keep up with the demand. The book came to be called simply “the Kinsey Report,” perhaps to spare the squeamish from having to pronounce the word that begins the title. And for those who actually read it, the Kinsey Report was an eye-opener, revealing that premarital and extramarital relations, homosexual intercourse, oral sex, masturbation, “petting to climax,” and a host of other practices were much more common than almost anyone would have guessed.

Reactions to the report were mostly favorable. A Gallup Poll showed that 58 percent of men and 55 percent of women thought Kinsey’s research was a “good thing,” while 10 and 14 percent respectively thought it a “bad thing.” Journalists spoke of a “chorus of praise” and “widespread public acceptance.” Kinsey himself called the response “much more favorable than we could have had any right to expect.” Of more than a thousand letters the authors received in the first month after publication, only six were unfavorable.

There were dissenters, of course. Clare Boothe Luce told a Catholic women’s group that “the Kinsey report, like all cheap thrillers, would fall into obscurity if so much attention was not paid to it.” Harold W. Dodds, president of Princeton University, dismissed the book’s “trivial graphs” and likened it to “the work of small boys writing dirty words on fences.” In a letter to the Reader’s Digest , Jackie Robinson of the Brooklyn Dodgers rejected the report’s implicit endorsement of promiscuity: “A man must show moral restraint to win honors in the world of sport. The athlete who fails at self-policing automatically and foolishly eliminates himself from championship company.” Many readers who paid $6.50 for the hefty tome found it tiresome to plow through 804 pages of dense academic prose in search of the good parts. Others scanned the statistics and wondered how they had missed out on all the fun.

While most of Kinsey’s fellow scientists praised the report’s honesty and importance, they tended to be more critical than lay readers. Some pointed to methodological flaws, including his all-white, all-volunteer sample group. Since the book was based on interviews, it was only as reliable as the subjects’ responses, which reticence or vanity could distort. The survey’s aggressive style of questioning, designed to overcome the interviewees’ shyness, also came under fire.

Such criticism obscures Kinsey’s most important achievement, the evidence of which is in your hands right now. By making