way of living that destroys nature and a more traditional way of living before industrialization. Ecological utopias may advocate a society that is more sustainable. According to the Dutch philosopher Marius de Geus, ecological utopias could be inspirational sources for movements involving green politics. Feminism Utopias have been used to explore the ramifications of genders being either a societal construct or a biologically "hard-wired" imperative or some mix of the two. Socialist and economic utopias have tended to take the "woman question" seriously and often to offer some form of equality between the sexes as part and parcel of their vision, whether this be by addressing misogyny, reorganizing society along separatist lines, creating a certain kind of androgynous equality that ignores gender or in some other manner. For example, Edward Bellamy's Looking Backward (1887) responded, progressively for his day, to the contemporary women's suffrage and women's rights movements. Bellamy supported these movements by incorporating the equality of women and men into his utopian world's structure, albeit by consigning women to a separate sphere of light industrial activity (due to women's lesser physical strength) and making various exceptions for them in order to make room for (and to praise) motherhood. One of the earlier feminist utopias that imagines complete separatism is Charlotte Perkins Gilman's Herland (1915). In science fiction and technological speculation, gender can be challenged on the biological as well as the social level. Marge Piercy's Woman on the Edge of Time portrays equality between the genders and complete equality in sexuality (regardless of the gender of the lovers). Birth-giving, often felt as the divider that cannot be avoided in discussions of women's rights and roles, has been shifted onto elaborate biological machinery that functions to offer an enriched embryonic experience. When a child is born, it spends most of its time in the children's ward with peers. Three "mothers" per child are the norm and they are chosen in a gender neutral way (men as well as women may become "mothers") on the basis of their experience and ability. Technological advances also make possible the freeing of women from childbearing in Shulamith Firestone's The Dialectic of Sex. The fictional aliens in Mary Gentle's Golden Witchbreed start out as gender-neutral children and do not develop into men and women until puberty and gender has no bearing on social roles. In contrast, Doris Lessing's The Marriages Between Zones Three, Four and