Physiology: The Nature of Sexual Response

Though billions of human beings down the ages have experienced sex, the question persists: What is it? The average man's or woman's answers are as uninformative as the paeans of poets, and not until a century ago did medical science tackle the question. Then even such pioneers as Krafft-Ebing, Freud and Kinsey relied on what their subjects told them — and gathered mostly emotion-laden impressions.

To Gynecologist William Howell Masters, 50, this sort of thing is not sufficiently precise or scientific. Ever since he graduated from the University of Rochester medical school in 1943, Masters has been determined to chart the basic physiology of sex. Next spring Little, Brown & Co. will publish Human Sexual Response, the extraordinarily detailed results of Dr. Masters' eleven years' work with his research associate, Psychologist Virginia E. Johnson.

Bed & Camera. Dr. Masters deliberately delayed his primary sex research until he was almost 40, a husband and father of two, a specialist in obstetrics and gynecology, and a medical professor at Washington University in St. Louis. In 1954 he persuaded the university to set up special laboratories containing a bed, electrocardiographs, electroencephalographs, biochemical equipment, flood lights and color-movie cameras. A primary purpose was to study sexual inadequacy in both sexes.

To avoid public controversy, Dr. Masters published nothing for five years, then reported his first findings in the relatively obscure Western Journal of Surgery, Obstetrics and Gynecology.

Now the controversy is unavoidable. To permit filming of detailed physiologic changes, many of Dr. Masters' subjects necessarily engage in what he calls "automanipulation," generally known as masturbation, and other stimulating techniques. As a result, the research program has made unique progress in mapping the sexual response of both men and women — in some cases, during coitus. Dr. Masters divides the female response into four phases that vary in both duration and intensity among different women, and even for the same women at different times. The typical progression: