What leads some women to form romantic and sexual relationships with men, a
nd other women to form intimate relationships with women? This article pres
ents a new conceptual paradigm for understanding women's sexual orientation
that is emerging from research in such diverse fields as social psychology
, sex research, evolutionary psychology, attachment theory, and neuroscienc
e. This approach acknowledges the potential plasticity of women's sexuality
and the emphasis that women place on close relationships as a context for
sexuality. Research also raises the possibility that for women the biologic
al determinants of sexual desire, attraction, and attachment are not inhere
ntly linked to a partner's gender. This article begins with a brief survey
of research on women's same-sex romantic and sexual relationships not only
in the United States today but also in other cultures and historical period
s. These and other findings are used to critique prevailing conceptual mode
ls of women's sexual orientation. Finally, key elements in an alternative p
aradigm are described.