"According to Agacinski, preventing same-sex couples from marrying is not a way of guaranteeing a heterosexual hegemony. The institution of marriage does not legalize heterosexuality, it regulates filiation. The point of the prohibition is, rather, to guarantee that every man and woman is inscribed ‘within the order of a humanity that is itself sexed and to ensure that he/she accepts that he/she will never be ‘the whole human’ (PS 33). If same-sex couples were able to marry, the inevitable outcome would be the legitimation of gay parenting, and that would endanger ‘the human, social and symbolic order ’. Nothing less."
Link to essay ("Who's Afraid of Gay Parents?") by Sylvie Duverger, in Radical Philosophy.
Agacinski's arguments can be said to hinge upon a natural law that decrees a certain way of participating in biological union as the only way of consummating that spiritual one, which seems, implicit in her argument, to be the raison d'etre of human existence. What can one really say to that?