The request that homosexual couples be acknowledged the right to marry and have children is the outcome of a complex process of cultural change, involving the notions of intimate relationship and marriage. Against the background of this process, the opposition to homosexual marriage as well as some arguments in its favour appear limited and indirectly supporting heterosexuality as the «natural» basis of marriage. Defining homosexual relationships «families of choice» as opposed to «biological families» denies that the latter are also social constructions. The tolerance argument hides the historical nature of marriage as an institution. An argument should be based instead on the awareness that marriage and family are social historical institutions, contesting and changing the terrain of negotiations over norms and values.