Simone de Beauvoir adopted Sylvie Le Bon in 1980. Beauvoir was seventy-two and Le Bon in her late thirties. By then, both were in a deeply intimate relationship of some twenty years, a relationship Beauvoir refused to call "lesbian" but described as "absolute". In spite of her life-long rejection of institutionalized marriage Beauvoir suggested that their adoption was "like marriage."

This paper investigates Beauvoir's adoption of Le Bon not as a legal means to "secure a literary heir" but as a queer kind of resistance against the bio-heteronormative family. It suggests that Beauvoir confounds historical and contemporary meanings of sexuality and family because her heterodox use of adoption blurs the boundaries of both. It argues that her characterisation of adoption as a marriage made the sexual profundity of her relationship with Le Bon legible, even as the "truth" of her family romance cannot be formulated in a phrase.