The National Organization for Marriage (NOM) objects to gay marriage because it's mostly about making couples feel “a certain way.”

The explanation comes from Dr. Jennifer Roback Morse, founder and president of the Ruth Institute, a project of NOM, the nation's most vociferous opponent of marriage equality.

“If you look at same-sex couples, both at what they say and their behavior, neither permanence nor sexual exclusivity plays the same significant role,” Morse told Salvo Magazine. “In other words, if you're in a union that's intrinsically not procreative, sexual exclusivity is not as important. Once you start thinking like that, you'll see that everything people offer as reasons why same-sex couples should be 'allowed' to get married – all of the reasons are private purposes. Sometimes it's nothing more than how it will make them feel. It's not the business of law to make people feel a certain way. When you see that redefining marriage is going to, in fact, redefine the meaning of parenthood, removing biology as the basis for parenthood and replacing it with legal constructions – then you see that there is quite a lot at stake in getting the definition of marriage right.”

Think Progress' Zack Ford commented: “Morse is arguing that any couple that can not biologically reproduce is incapable of monogamy or life commitments to each other, a characteristic that applies to many straight couples as well. This argument neglects both the important legal protections of marriage and the fact that many same-sex couples raise families.”

(Related: NOM claims gay college resident advisers are pressuring students on gay rights.)