Pew poll: Same-sex marriage support rising in United States WASHINGTON, June 6 (UPI) -- U.S. support for same-sex marriage is rising, with 51 percent of American in favor of allowing gays and lesbians to marry, a Pew Research Center survey found. While 42 percent say they oppose legalizing gay marriage, 72 percent of those surveyed say legal recognition of same-sex marriage is inevitable. That number includes 85 percent of gay marriage supporters and 59 percent of opponents, Pew said Thursday. The Pew survey found opposition to gay marriage, as well as the social acceptance of homosexuality, stems largely from religious concerns. Pew said 45 percent of Americans think homosexual behavior is a sin, with an equal number saying it is not. Nearly nine-in-10 Americans (87 percent) personally know someone who is gay or lesbian, up from 61 percent in 1993. About half (49 percent) say a close family member or one of their closest friends is gay or lesbian. Twenty-three percent said they know a lot of people who are gay or lesbian, and 31 percent said they know a gay or lesbian person who is raising children. Pew said there is a strong link between those personal experiences and attitudes about same-sex marriage, with 68 percent of those who know a lot of people who are gay or lesbian in favor of gay marriage, compared with just 32 percent of those who don't know anyone who is gay or lesbian. The national survey was conducted May 1-5 among 1,504 adults. The margin of error was 2.9 percentage points.