What was the impact of the making of sex hormones on the conceptualization of sex differences? To answer this question I have to highlight another function of research materials. Not only did the availability of research materials have an impact on the interrelationship between the groups involved in research on sex hormones, but also research materials functioned as carriers in the transmission, and consequently the selection of knowledge claims. To understand the role of research materials in the development of research, we can trace the movement of research materials from one group to another.

In the period of the introduction of the concept of sex hormones, the three groups involved in research on sex hormones focussed on different research questions. The gynecologists were particularly interested in the role of female sex hormones in female disorders associated with the ovaries, and in processes of reproduction in the female body. Gynecologists tentatively began to wonder if and how the internal secretions of the ovaries might control ovulation, menstruation and pregnancy. The pharmaceutical companies followed up these claims by producing ovarian preparations for therapeutic purposes. The laboratory scientists shared a broader interest. Besides issues of reproduction, laboratory scientists were particularly interested in the role of both female and male sex hormones in the growth and development of the body in general, and more specifically in the process of sexual differentiation—the development and maintenance of both the sexual organs and the secondary sexual characteristics.

In the early period, when the three groups still worked independently from one another, all claims were investigated with equal attention. This situation changed drastically from the moment the groups had to rely on each other for the supply of research materials. With the transfer of research materials from one group to another, knowledge claims specific to the group in control of the research materials were also transferred. In this process a selection of knowledge claims took place: some claims became stronger, others weaker.

The first time this happened was in the period when scientists were using human female gonads in their research. Only the gynecologists could easily gain access to this type of research material. To translate then – claims from animals to human organisms, all groups had to rely on the gynecological clinic, as the only place where human gonads could be obtained. Here we see the first selection of claims. The claims attached to the male gonads could not be transferred from animals to humans because a medical practice for the provision of human testes did not exist. In this way, the knowledge claims that gynecologists attached to female sex hormones became stronger than the claims of the other groups. Thus, claims concerning the role of female sex hormones in female disorders and female reproduction gained more momentum than claims concerning sexual differentiation and male reproductive functions.

This initial selection of claims was further reinforced in the period when scientists began to use human urine. As we have seen, human urine as a source of research materials stimulated research on female sex hormones enormously, because female urine could easily be obtained and processed. Because the gynecologists could gain access to the urine of women more easily than the other groups, the process of selection of claims was further strengthened in the direction of their own interests. With the transfer of the urine of their female patients from the gynecological clinic to the laboratory and the pharmaceutical companies, the claims concerning women’s diseases and reproduction were also transferred. Particularly during the period when urine was becoming established as a source of research materials, claims about the interrelationships between female sex hormones, women’s diseases and reproduction became stronger: gradually, they became the major focus on the research agenda of the three groups.

Because both methods and research materials were well developed and easily available, more and more scientists became involved in research on female sex hormones. Through the 1920s and 1930s, the number of publications on female sex hormones increased steadily, and far outnumbered those on male sex hormones.18 In the urinary period, both the laboratory scientists and the pharmaceutical companies became definitely committed to the specific interests of the gynecologists in female sex hormones. Since the 1920s, all three groups have shared a mutual interest in female sex hormones as a field that has gradually developed into big science and big business.

Summarizing the role of research materials in the development of sex endocrinology, we can conclude that in the selection process of knowledge claims that resulted from the transfer of research materials, women and reproduction became the central focus of research. In the triangle gynecology-laboratory-pharmaceutical industry, the male gradually disappeared from the forefront as an object of research. Although most actors were male, the object of research was almost entirely female. Knowledge claims linking men with reproduction could not be stabilized because there did not exist an institutional context for the study of the process of reproduction in men. Although the need for the establishment of a separate and distinct specialty for the study of the male reproductive system was suggested as early as 1891, not until the late 1960s was andrology institutionalized as a medical specialty.19 These differences in the institutionalization of the life sciences exerted an all-pervasive impact on the development of reproductive research. Consequently, the development of knowledge about male reproduction was long delayed.20

CONCLUSIONS

This focus on the material conditions for hormone research highlights a feature that is of major importance in the development of science. Scientists do not construct facts and artefacts isolated from their social context. In order to make sex hormones, scientists had to create networks with other social groups outside the laboratory. The construction of sex hormones took place in networks formed between three groups: the laboratory, the clinic and the pharmaceutical industry. These networks were of vital importance in the study of sex hormones. Had laboratory scientists not succeeded in capturing the Interests of the pharmaceutical industry, research on sex hormones would have stayed inside the walls of the laboratory.

Research materials played a crucial role in the building of these networks. This reconstruction illustrates how research materials became the pivot on which the relationships among the different groups involved in the making of sex hormones hinged. By tracing how scientists gained access to research materials, it became obvious how the different groups, at first operating independently, gradually became enmeshed in a network of dependences and alliances. The nature of their relationship changed from one of independence to one of mutual dependence. Research materials functioned as an organizing medium, bringing the groups together and shaping the relationships between them. Research materials were thus instrumental in linking the practices of the laboratory to theirsocial context: the clinic and the pharmaceutical industry.

This reconstruction also illustrates how the scientific endeavor produces not only theoretical claims. Through a close cooperation with the pharmaceutical companies, laboratory scientists transformed the theoretical concept of sex hormones into material realities: chemical products that could circulate outside the walls of the laboratories. In this respect, there remains one major question to be answered: what happened when sex hormones left the laboratory? In the next chapter we follow the laboratory scientists, the pharmaceutical companies and the medical profession in the next phase of the creation of sex hormones: the transformation of sex hormones into specific drugs.