Over the past decade, the epidemiological landscape of sexually transmitted infections (STIs) has changed significantly. The most recent French data indicate reduced awareness of current preventive measures regarding the HIV epidemic and a relaxation of preventive behaviors, particularly among gay men. These findings are confirmed by a resurgence of certain STIs, observed since 1997–1998 in France as well as in other European countries. The epidemic is now increasingly affecting women and socially and economically vulnerable populations, particularly migrant populations: one in three HIV-positive individuals is from sub-Saharan Africa, and women account for the majority of reported cases. Risks associated with sexual activity also include the occurrence of unplanned pregnancies, the majority of which end in voluntary termination of pregnancy. Recent changes in the French contraceptive landscape—marked both by the continued, albeit less pronounced, trend toward medicalization and by the widespread use of condoms among younger generations—prompt us to examine the complex links between preventive practices regarding STIs and contraceptive practices, and on the potential of emergency contraception (EC) to address contraceptive failures, which remain frequent. These various changes are occurring within a social context whose evolution over the past few decades has been characterized, among other things, by a diversification of emotional and sexual experiences, as well as by the increasing precariousness of certain social groups affected by unemployment and the difficulties of daily life. These social changes are not without impact on sexual practices and, a fortiori, on risk-taking, as evidenced by a recent survey conducted in Great Britain.[chapter excerpt]