These assumptions of naturalness were nevertheless challenged from several directions. One was evolutionary biology. Charles Darwin’s Descent of Man in 1874 offered a detailed account of ‘sexual selection’ as a mechanism of evolution alongside the ‘natural selection’ emphasized in the Origin of Species. In his unemphatic style Darwin took the issue of sex out of the hands of theologians and moralists and made it a question of observation and comparison of the behaviour of different species. More, biologists became interested in why sex existed at all, and gradually developed an account of the evolutionary advantages given by sexual reproduction. Though one spin-off from Darwinism has been the ‘naked ape’ claim that men’s supremacy over women is an evolutionary law, in the long term the effect has been unsettling for patriarchy. Merely by offering explanations of sexual behaviour, evolutionary biology entrenched the idea that these patterns were in need of explanation, that they were somehow problematic.

The scientific impact on the field of argument deepened with the advent of doctors interested in sexuality and gender and the creation of a semi-medical speciality which later came to be called ‘sexology’. Medical and medico-legal case histories provided the first base for an exploration of the forms of human sexuality as a natural phenomenon. The first monument of this work was Krafft-Ebing’s Psychopathia Sexualis (first edition 1886, numerous expanded editions later), which catalogued with horrified fascin­ation the many forms of ‘degeneracy9 from transvestism and homoeroticism to eating shit and liking to be whipped. The anthropology of sexual variation was developed much more lovingly by Havelock Ellis, whose Sexual Inversion, the first volume of Studies in the Psychology of Sex to be published, appeared in 1897. But the central figure in this movement of thought was undoubtedly Sigmund Freud.

Particularly in ‘Three Essays on the Theory of Sexuality’, Freud’s arguments wrecked the notion of natural fixed characters for the two sexes. His emphasis on ‘bisexuality’ in human emotions, and his insistence on the importance of conflict within emotional life, made it difficult to see any pattern of sexual character as completely settled. More, in his analyses of the ‘Oedipus complex’ he showed how patterns of emotion in adulthood could be grasped as resolutions of the conflicts of development, and how different childhood situations could twist and reconfigure every aspect of emotional life.

Freud’s importance in the history of ideas was not so much in popularizing the theme of sex, which a good many others were also doing. It was in providing a method of research – ‘psychoanalysis’ itself – which generated masses of new information about emotional life and human development, and led to a focus on the life history as the unit of analysis rather than the species, the body or the syndrome. The psychoanalytic life history forced attention to the details of relationships, the configurations of families, in short to the social contexts of emotional growth. Psychoanalysis thus produced detailed and sophisticated accounts of femininity and masculinity as psychological forms constructed by social processes. Ironically this was not Freud’s intention – he clung to the hope of biological explanations of psychology – but the logic of his methods led inevitably towards the social.

The concept of bisexuality was one of Freud’s devices for understanding homosexual attraction. This was a standing problem for accounts of gender which based everything on biology or on the attraction of opposites. And it was a ‘problem’ whose salience was increasing, as the late nineteenth century sharpened the social definition of ‘homosexuals’ as a group apart. This was partly by new forms of criminalization (one of whose first victims was Oscar Wilde), partly by medical definitions of homosexual behaviour as pathology and partly by the political and cultural response of homosexual people themselves. Authors such as Karl TJlrichs in the 1860s and 1870s, and more famously Magnus Hirschfeld from the 1890s on, had one foot in scientific sexology and the other in the movement to liberalize social attitudes and laws. Hirschfeld’s Scientific Humanitarian Committee expressed the blend nicely. The immediate outcome was a naturalistic theory of homosexuality, the idea of a ‘third sex’. This ran counter to the direction Freud was taking, and so far as it supposed a physiological basis for homosexual preference, can now be regarded as falsified. It was a politically defensive idea, a reply to denunciations of homosexuals as moral degenerates. Yet in the context of the early twentieth century it had force as the only explanation of the stability of homosexual desire over a lifespan. In this sense it added to the voices questioning the taken-for-grantedness of the dichotomous sex categories.

Freud lacked, notoriously, a theory of social structure. If the conventional family were taken as a given, both his analysis of psychosexual development and his medical treatments could become a defence of the patriarchal status quo. They certainly did among his followers, especially after the emigration of psychoanaly­sis to North America in the 1930s. Freud himself was a kind of libertarian but not a political radical – and it was mostly among radicals that the conventional family, and especially its division of labour, came into question.

The issues raised by the Utopian colonies in the early part of the century, and by socialist theorists of the mid-century, gained extra force in the context of the ‘new unionism’ of the 1880s and 1890s, the unionization of unskilled workers. Attempts to form unions of working women ran into obstacles that were not met when unionizing men. Partly this had to do with direct resistance from men: unions controlled by men often would not accept women members. It also had to do with the specific kinds of paid work that women were usually employed to do, in domestic service and food and clothing industries, and with the demands placed on them for work in their own homes by husbands and other relatives.

Women in the socialist movement, for example Clara Zetkin, argued that socialist ideas and practices must be rethought to deal with the oppression of working-class women. They assumed that the sexual division of labour could be changed and began organizing to do it. In the first decade of the twentieth century strong women’s movements developed in the socialist parties in Germany, the United States and elsewhere. Under their pressure, working-class organizations cautiously began exploring co-operat­ive childcare, public laundries, communal living arrangements and community-controlled education as practical forms of the socialization of childcare and housework. For a short while this became the policy of the revolutionary government in the Soviet Union, urged on by Alexandra Kollontai.

It did not last. With Stalinism in the Soviet Union and the freezing of Western socialism after the 1920s, these policies were completely marginalized. (By 1937 George Orwell could include ‘feminists’ with sandal-wearers, nudists and vegetarians in a list of unwanted cranks haunting socialist conferences.) Socialist feminism had, nevertheless, made a theoretical breakthrough. It had placed what we now call the ‘sexual division of labour’ on the agenda for analysis and explanation, as firmly as the question of sexuality had been placed there by Darwin and the sexologists.