Meghan McCain, the daughter of Arizona Senator John McCain, on Friday took a swipe at Rick Santorum's opposition to gay marriage.

McCain made her remarks a day after Santorum compared gay marriage to polygamy when challenged by students at a campaign stop at New England College in Concord, New Hampshire.

In a reference to Santorum's controversial 2003 remarks in which he linked gay sex to “man on dog,” McCain told MSNBC host Thomas Roberts: “There's a difference between being against marriage equality and then equating same-sex marriage to bestiality.”

“I mean it's so dated and it's so gross,” she added before she reiterated her support for gay marriage.

“It's far off the course of mainstream America, and it's enough for me just to say goodbye,” she said. “If you nominate someone like Rick Santorum, I guarantee he will lose.”

On her father's opposition to the institution, she said: “My father is hopefully going to be the next one I can work on, and he's sort of coming around … [H]e's 75 years old, so it's a bit different.” (Watch the exchange at Equality Matters.)