A new poll has Mitt Romney edging out Newt Gingrich as the most trusted GOP presidential candidate on gay marriage.

According to the Washington Post/ABC News poll released Tuesday, 25 percent of leaned Republicans say they trust Romney the most with social issues such as abortion and gay marriage. Gingrich trails with 15 percent, followed by Michele Bachmann (13%), Ron Paul (12%), Rick Perry (7%), Rick Santorum (4%) and Jon Huntsman (3%). Six percent of respondents said they didn't trust any of the candidates on social issues.

Romney has said he favors an amendment to the U.S. Constitution that would define marriage as between a man and a woman.

At a town hall in October, Romney said he opposed marriage for gay couples because “the ideal setting to raise a child for a society like ours is when there's a man and a woman in the marriage.”

When pressed on civil unions, Romney said he could only support a limited partnership for gay couples which include “such things as hospital visitation rights and similar things.”