Begging The Question

Donald Sensing attempts to defend the idea that the existence of childless heterosexual couples is accidental, and therefore doesn't affect the validity of the "homosexual couples can't get married because they can't have kids" argument:

As a social institution, marriage is defined in aggregate, not in particular. This fact argues against a Nominalist position that if two same-sex persons obtain a marriage license, that they are in fact married. It also shows why the pro side's snark that many male-female married couples never have children is irrelevant: out of any random 100 heterosexual marriages, the overwhelming majority will conceive children of their own, within the marriage bond, but out of any 100 same-sex unions, exactly zero will do so. Hence, the lack of children in a small minority of male-female marriages is accidental to what marriage does and what it is for, but the inability of same-sex unions to have children within the bond is inescapably central to their relationship.

The statistics he uses to show that childless heterosexual couples should be grouped with homosexual couples depend on grouping all heterosexual couples together. What if I pointed out that, while out of any random 100 fertile couples the majority will have children, exactly zero out of 100 couples in which at least one partner is infertile will have children. Doesn't that prove that childlessness among fertile heterosexuals is accidental and unimportant to whether their unions are really marriages, but that infertile couples are a whole other story -- you can call them married, but they can't be.