While in India especially the definition of the brother-sister relationship is organized in connection with the marriage alliance and the ritual construction of descent, it is quite different in contemporary European kinship. The analysis of this relationship is based on three novels and three films considered as ethnographic accounts. In these fictions, ambiguity and tension prevail in the relationship between opposite sex siblings: in the novels, it is a case of fusional or even incestuous love between brother and sister, sterile love that devalues any other family relationship; in the movies, the preeminence of the sister over the brother and the lies of the sister to educate her brother are themes that feature heavily. From these examples it is clear that the choice to be made lies between incest and filiation, while marriage does not appear as an important dimension of the social construction of kinship.