Rick Santorum signs pledge to ban same sex marriage and pornography

Rick Santorum has become the second Republican presidential candidate to sign a "pro-marriage" pledge vowing to fight against same sex marriage, Sharia law and pornography.

"When I first read it, I was taken aback by it. I can't argue that I wasn't," he told CNN on Sunday.

Rep. Michele Bachmann (R-MN) was the first presidential candidate to sign the pledge, created by The Family Leader, a conservative, Iowa-based Christian group.

"Our goal is to send out The Marriage Vow to the candidates, including President Obama, by July 15th and have his/her signed document returned to us by August 1st. We can then publicize their responses at the Iowa State Fair and the Iowa Straw Poll," The Family Leader CEO Bob Vander Plaats said.

By signing the pledge (PDF), Santorum and Bachmann vowed to remain faithful to their spouses and support a constitutional amendment banning same sex marriage, as well as agreeing that same sex marriage was akin to polygamy.

They both also promised to ban "all forms of pornography and prostitution, infanticide, abortion and other types of coercion or stolen innocence" and only appoint conservative judges.

"I pledged personal fidelity to my wife when I was married to her," Santorum added. "And pledged the same, that I would not involve myself in any other relationships with anybody else who is married. So that's a pledge I've taken and I take every single day when I - as a married person - and feel very comfortable making that public statement."

The document also implies that homosexuality is a choice.

"No peer-reviewed empirical science or rational demonstration has ever definitively proven, nor has even shown an overwhelming probability that homosexual preference or behavior is irresistible as a function of genetic determination or other forms of fatalism," according to the Christian group.

Watch CNN's interview with Rick Santorum below:

With prior reporting by David Edwards