In a paper given before the third annual meeting of the Academy of Psychosomatic Medicine in October 1956, Chicago obstetrician and gynecologist William S. Kroger stated that “even though the American woman looks and acts as though she is capable of sexual gratification, many do not have orgasm during intercourse.” Kroger declared these women frigid and described several types of frigid women. According to Kroger, some women were frigid because they thought they were not supposed to feel sexual pleasure because sex was “indecent” and others who perhaps become aroused but failed to achieve orgasm. But the label of frigidity also applied to women for “whom sexual response occurs only after clitoral stimulation.” Women were truly frigid who had a “total incapacity for vaginal orgasm.” Because he defined true frigidity as a lack of vaginal orgasm, Kroger told his audience that “circumcision of the clitoris is valueless” as therapy.

Kroger explained the importance of differentiating between the clitoral and vaginal orgasm, noting that the “vaginal and clitoral theories for evaluating frigidity and orgasm differ so much that discussion cannot be attempted without defining them.” The majority of the followers of Sigmund Freud, Kroger stated, “adhere to the vaginal theory of orgasm and label 75 per cent of American women frigid” because they cannot reach orgasm vaginally without clitoral stimulation. Many followers of Freud advocated this theory, in opposition to, Kroger wrote, what “a disciple of Kinsey or a proponent of the clitoral theory” believed. Those who maintained women had clitoral orgasms thought “less than 25 per cent of these same women are frigid.” Kroger went on to note that this “difference of opinion” confused physicians and was “disturbing to millions of American women.” This confusion had only been “compounded” by the “barrage of lay articles, medical treatises, and public and private discussions” about whether a healthy, mature female orgasm was clitoral or vaginal.

Freud, Kroger noted, originated the idea of distinct and hierarchal female orgasms in the early twentieth century, with the vaginal orgasm promoted by some as not just the “optimum type of sexual response,” as Kroger called it, but also as the only one that signified a woman had reached healthy feminine sexual maturity. This theory of the primacy of the vaginal orgasm remained popular from the mid-1940s through the mid-1960s, a period coinciding with the popularity of psychoanalysis in general.