Moreover, to contend, as same-sex couples do, that they can adopt children or rely on sperm donors merely accentuates the paradox, for they reveal themselves as dependent on precisely the sexual fertility which they forsake and the procreative function they have renounced. There would be no gays in the absence of the bonded heterosexual couple that rears children and is socially constrained to provide for their future. There is a debt to be paid in the only way possible: do not insult or damage the institution that gave you existence and continues to sustain it. The fact often adduced by skeptics that not all heterosexual unions are fertile or permanent is beside the point; the ancestral purpose of marriage as an institution remains intact."
David Solway, The Problem with Gay Marriage