In the morning of September 14, 1953, millions of American women felt uneasy and thousands of families were again in trouble, thanking to the shameless research by the sex professor–Dr. Alfred Kinsey. Many women suddenly discovered that their lives lacked one critical element–the sexual orgasm. Conservatives were also furious about Kinsey’s Reports. Rev. Bill Graham claimed that Dr. Kinsey had been grossly mistaken about millions of born-again women who had vowed for being chaste in their lives.

The notorious book–Sexual Behavior in the Human Female was in fact a serious academic monograph detailing about the sexual experience and behavior among American women. It was a dry book full of tables and arcane descriptions. Furthermore, men’s dark secrets had already been exposed to the public five years ago in the book– Sexual Behavior in the Human Male. These two books (the Kinsey Reports)were sold 300,000 each, a number which almost all academic writers would envy.

The 2004 movie–Kinsey– documented both Kinsey’s fascinating personal life and his controversial research. In the post-Monica era when people are questioning sex and morality, this movie was timely and also necessary. Human sexuality is not a taboo, and talking about it will not corrupt the society.

The importance of the Kinsey’s Reports is that it laid out the foundation for us to further understand ourselves. Sex is one of the (if not the only one) important parts of life. Without it, human beings would not exist.

Given our current knowledge, the Kinsey Reports presented nothing earthshaking. However, sixty years ago, as shown in the movie, most college students had no idea about the reality of sex. Kinsey had to illuminate them that oral sex was not dirty (Monica Lewinsky probably already knew this fact). You can kiss partner’s genital to help achieve orgasm. This was radical. No one dares to speak it publically even today. Nevertheless, it was the ignorance of sex knowledge in college students that provoked him to initiate a study on human sexual behaviors.

Kinsey’s idea to study human sexual behaviors but not the emotion(love) might seem odd by current standard. However, in the earlier twentieth century, behavior research was dominating psychology in the United States. Cognitive theory was in its infancy. Kinsey certainly could not devise a new theory in psychology. Actually, he was not interested in psychology at all.

Furthermore, as Kinsey later argued, there was no way to objectively measure love. Philosophically, Kinsey’s approach is perfectly sound. Hypotheses should be specific, measurable, and refutable.

Kinsey’s research was essentially an exploratory study. His original plan was to collect 100,000 cases. This is a fairly large number for a human study even now. But Kinsey was an obsessive person. He had collected more than 5 million gall wasps during the previous 20 years as a zoologist. It is true that he might have no idea about sample size calculation and sampling methods. Nonetheless, before he died, his research team had interviewed more than 16,000 people and he personally did more than 6,000 of them. That required a lot of efforts, for a typical interview might last more than an hour.

But one fatal mistake Kinsey had made was that his sample was not a random sample. His study subjects were recruited by referral. Participants included many prisoners, prostitutes, and sex offenders. Because of this, people labeled his study as junk science. However, this is an unfair judgement. In 1940s, there was little knowledge about probabilistic sampling, especially for such complex problems. As the American Statistics Association committee (members included Cochrane and Tukey) pointed out, probably only twenty people in the world could fully understand the sampling problems in Kinsey’s study. Furthermore, human sexuality was an uncharted territory then. It would be unrealistic to randomly sample people and ask them their sexual experience.

In fact, the way that Kinsey recruited his participants was comparable to that of current research. For any study, representativeness through random sampling is less important than the validity of measurement and study implementation. In England at the same time, Sir Richard Doll (who just died at the age of 92) investigated the relationship between smoking and lung cancer among British doctors. Nobody questioned his study design. Today, widely cited research such as the Harvard Nurse study and the Health professional study was formed in narrowly defined populations. What do you think about the representativeness of these studies? They are doctors and nurses! Their health behaviors are certainly different from those of most common Americans.

Anyway, Kinsey was not a statistician and had little training in sociology or psychology. He carried out his sex study the same way as what he did in gall wasp research–collecting a large number of subjects and reporting the variation among them. He tended to overgeneralize his results though. Indeed, he ignored the heterogeneity of his sample by lumping special populations such as prisoners with college educated population. Some tables were based on sexual experience from handful subjects. The statistical methods in his reports were rudimentary (but statisticians then were limited in some simple and hand calculations too). He was also confused about the proportion and rate in a few calculations. Fortunately, in a later reanalysis among subgroups, Kinsey’s conclusions were largely unaltered. It was not unexpected. Because his sample was so large and most of his participants were common Americans, small deviation would not affect the general conclusions.

The merit of Kinsey’s research was the broad and deep assessment on human sexual behaviors. He devised more than 500 questions/items for the study. His interviewers were highly trained by Kinsey himself through simulated interviews (which was depicted well in the movie). All of his assistants had undergone a thorough questioning process about their own sexual experience. During the actual interview, they maintained a candid attitude with relentlessly probing. Although his measurements were fiercely criticized by his peer researchers then, his interviewing methods were considered high quality even by today’s standard.

Almost sixty years later, the Kinsey’s Reports still irritated conservative people. During an NPR radio talk before the movie came out in Nov 2004, conservative listeners kept calling in to denigrate Dr. Kinsey. They complained that his research caused the wide spread of homosexuality, pre-marital and extramarital sex, and HIV and STD. Apparently, these hypocritic conservatives refuse to accept the fact that these sexual phenomena existed before Kinsey’s study. Furthermore, Kinsey didn’t advocate promiscuity. He merely observed and reported human sexual activities. Given the liberal atmosphere then, if Kinsey hadn’t done the study, somebody else would do it. It is just a matter of time.

The movie is a fine one by any standard. I was personally interested in one scene (widely available as a movie trailer). When Kinsey told his wife that he had extramarital sex with his research assistant (Martin), his wife was furious. She questioned him: “I didn’t sleep with other men because I love you.” He literally stated that sex could be separated from love. Obsessed by his scientific findings, Kinsey apparently missed the most important point–love and sex are interweaved.

However, the topic of love and sex is so complicate that it deserves its own chapter. Briefly, love and sex are different constructs. Love contains much more contents than sex does. Love is a high level emotion, while sex is a primitive behavior which may be misguided by environment. Love is multidimensional and sex is just one part of it. Therefore, it would be mistaken to say that Clinton loved Lewinsky because they had sex (repeatedly). It would also be premature to label one infidel just because he or she has a brief crush on other people. Furthermore, in the era of internet, it is not uncommon to see somebody having a virtual affair with other people while remaining loyal to his partner. A long-lasting love weighs much more than online gathering, erotic joking, or even a one-night-stand.