Although studies show that women who have sex with women (WSW) have poorer sexual health and more limited access to health care for gynecological problems than other women, the social processes giving rise to such health differences have not, so far, been explored. These processes may be formed in response to a dominant social norm, which assigns women to a heterosexual and monogamous sexuality. Based on data from a national random survey of sexuality (N = 6,824), enriched by qualitative interviews with WSW (n = 40), this analysis shows that bisexually active women had similar socio-demographic profiles to heterosexually active women, whereas homosexually active women appeared to be more highly educated than other women and less likely to live as couples than bisexually active women. Bisexually active women had more diversified sexual trajectories and sexual networks than other women. Chlamydia prevalence was found to be higher among bisexually active women, and homosexually active women reported fewer medical consultations for gynecological reasons. These analyses highlight the need to deconstruct the binary classification of homosexual versus heterosexual women. Because of constraint by the monogamous heterosexual norm, bisexually active women were less likely to be tested for sexually transmitted infections, and homosexually active women were less likely to have had gynecological follow-ups.