In the measuring of female sex hormones it is obvious that the preferences for specific tests are specific to various disciplines. But what about the measuring of male sex hormones? How did scientists attach the label “male” to substances?

Using a logic similar to that used in the study of female sex hormones, scientists decided that the label “male sex hormone” should be attached to substances that could induce the recovery of the organism after removal of the testes. In theory, any characteristic that changed following castration was considered suitable as an assay. Research on male sex hormones differed from the study of female sex hormones, in that the development of tests for male sex hormones was the exclusive field of laboratory researchers, primarily physiologists and zoologists, some animal psychologists, and later biochemists. One of the first tests for male sex hormones was comb growth in castrated roosters: the comb test, which has a long history. The first report describing the effect of the removal of testes on comb growth was published as early as 1849 by the German physiologist Berthold, and is generally considered by endocrinologists to be “the first proof of endocrinological function as we know it today” (Beach 1981:328). The Amsterdam School described this test in its essentials:

The rooster wears a comb, which is, so to speak, the flag that is hoisted to announce the presence of his testes to the hens. On removal of the testes the flag is lowered: the comb atrophies and the rooster has become a capon.

(Tausk 1978:54)

In addition to the comb test, physiologists applied assays based on changes in fat deposits, body length and weight, and hair growth, in rats and guinea-pigs. The variety of tests illustrates the interest of physiologists in all aspects of the physiology of animal organisms. As in testing for female sex hormone, animal behavioral tests were also introduced, specifically tests that involved mating behavior (Beach 1981:335). The chemical isolation and identification of male sex hormone in the 1930s enabled scientists to attach the label “male” to hormonal preparations following the analysis of their chemical structures. In contrast to female sex hormones, biochemists did not develop color reaction tests.

In the 1930s the comb test was the one most widely used. This testing method was accepted as the standard test for male sex hormones in 1935 at the Second Conference on Standardization of Sex Hormones in London. Consequently, the activity of testes preparations was expressed in rooster or capon units. Remarkably, the development of tests for male sex hormones involved less debate than did the development of tests for female sex hormones. As we have seen, the debate over the test procedure for female sex hormones emerged from criticism of the quality of commercial ovarian preparations, expressed particularly by gynecologists. The absence of such a debate about male sex hormones reflects a lack of professional concern with the quality of male hormone preparations by clinicians.