David Blankenhorn said in an op-ed article in The New York Times he was throwing in the towel and called for the acceptance of homosexuals being allowed to marry.
"Whatever one's definition of marriage, legally recognizing gay and lesbian couples and their children is a victory for basic fairness," wrote Blankenhorn, founder of the Institute for American Values.
But Peter Sprigg, a senior fellow at the Family Research Council, told the Times he suspects Blankenhorn changed his tune out of fear of offending homosexuals and other supporters of same-sex marriage.
"He has thrown marriage under the bus for the sake of the homosexual movement," Sprigg said.
Notable deaths of 2014 [PHOTOS]