“When you meet a human being,” Freud has said, “the first distinction you make is ‘male or female’, and you are accustomed to making the distinction with unhesitating certainty,” (Freud 1933:120 as cited in Strachney 1965). In the early decades of the twentieth century, scientists were less confident about the distinctions between female and male characteristics:
Although the classification into male and female sex hormones seems self-evident, it is nevertheless rather difficult to define; the changing opinions hereabout have succeeded one another so fast in such a small number of years, that at present it looks like chaos…. The major problem is that precise notions associated with the words male and female are, alas, merely the property of the laymen, and fade away more and more if one becomes acquainted with the progressing experimental-biological research. We find it increasingly difficult to define which observed characteristics can be considered decisive for our judgement: male or female.
(Jongh 1936:5, 306)
Beyond the Natural Body focuses on this episode in the 1920s and 1930s in which scientists became confused by their own assumptions about sex and the body.