Gay marriage opponent Rick Santorum was booed in New Hampshire yesterday during a heated debate in which an audience member asked how marriage equality would harm him.

The US Republican presidential candidate recently emerged second place in the Iowa caucuses as the national race for the party’s nomination heats up.

At the College Convention 2012 in Concord, New Hampshire, the second state to hold votes on the question, he was grilled on how equal marriage would affect him negatively by Rhiannon Pyle, 17.

He said: “Marriage is the union of a man and a woman. God made men and women. Men and women come together in a union to have children. It should be valued and have privileged status over people who want to have a relationship together.

“The uniqueness of marriage is it provides an intrinsic good to society. It’s the union that causes children to be born and raised in an environment that’s a birthright.

“When we deny children that birthright by saying other types of relationships are okay, I think we are harming children.”

After repeatedly calling for quiet during the talk, in which he compared gay marriage to polygamy, the boos were reserved for Santorum’s exit.

He repeatedly asked Pyle: “What about three men? If you think it’s okay for two, you have to differentiate for me why you’re not okay with three. Any two people, or any three, or four.”

Santorum is currently the subject of scrutiny for comments about Medicaid he made at the weekend.

Video footage appeared to show the presidential hopeful saying: “I don’t want to make black people’s lives better by giving them other people’s money. I want to give them the opportunity to go out and earn the money.”

The former senator insisted he had not meant to refer to African Americans but had tripped over his words, saying the word was actually closer to “blah” than “black”.