Sullivan also argues that the relative monogamy of lesbian marriage will help to increase marital monogamy overall. I rebutted that argument in “Code of Honor.” More recently, however, in “Heather Has 3 Parents,” and “Seeing the Slip,” I showed how lesbian marriage has even more potential to undermine monogamy than gay marriage. That’s because many lesbian married couples who mother create de facto three parent families (which include biological fathers). That creates the potential for legal recognition of three parent families, which in turn will eventually lead to legalized polyamory. That, in turn, would remove social support for monogamy, which would have just the sort of negative consequences for heterosexual marriage that Andrew Sullivan warns of.