C'mon now, illustrations of a slippery slope oughtn't start so far down the hill. So, what about a post-menopausal mother marrying her adult son? If "consentin

C'mon now, illustrations of a slippery slope oughtn't start so far down the hill. So, what about a post-menopausal mother marrying her adult son? If "consenting adults" is the standard, it must be sanctioned as "marriage," yes? For the record, I'm not really against gay marriage, but I am staunchly against inconsistent reasoning in service of realpolitik.