WATCH: Australian Prime Minister Advocates Marriage Equality

The prime minister of Australia took a strong stance in favor of same-sex marriage during a nationally broadcast forum Monday.

Prime Minister Kevin Rudd was clarifying his stance on marriage equality to Matt Prater, a pastor of the New Hope Church, who asked about his position on the issue. Rudd cited to both science and scripture in defense of his support.

"I do not believe that people, when they are born, choose their sexuality," Rudd said. "They are gay, if they are born gay. ... And therefore, the idea that this is an abnormal condition is just wrong."

Prater then asked Rudd how he reconciled his views with the "biblical definition" of marriage as a union between one man and one woman, during the Q&A session on the Australian Broadcasting Corp.

"Well, mate, if I was going to have that view, the Bible also says that slavery is a natural condition," Rudd responded, to the applause of the crowd. "Because St. Paul said in the New Testament: Slaves be obedient to your masters. And therefore we should have all fought for the Confederacy in the U.S. Civil War."

"If we get obsessed with a particular definition of that through a form of sexuality, then I think we are missing the centrality of what the Gospel ... is all about," he said. "And therefore, if you think homosexuality is an unnatural condition, then frankly I cannot agree with you based on any element of the science."

The prime minister, running for his third term, has promised to hold a vote in Parliament on the issue within 100 days if his party wins the election, which will take place Saturday. His opponent, Tony Abbott, is against marriage equality.

Watch the prime minister's response below.