WASHINGTON: A majority of Americans support same-sex marriage, but that doesn't mean they are accepting of homosexuals displaying affection in public, a study published on Thursday suggests.

Sociologists at Indiana University asked more than a 1,000 people how they might feel about seeing couples hold hands, kissing on the cheek and French kissing in a park. 97 per cent of heterosexual respondents said they were OK with straight couples holding hands in public. However, only 62 per cent approved of gay men doing so. 95 per cent approved of men and women kissing on the cheek, but 55 per cent thought likewise if the couple in question were both men. 50 per cent, meanwhile, approved of a straight couple publicly engaging in French kissing, but only 22 per cent thought it was acceptable for a gay lovers to do so. The level of approval for lesbian couples was a bit higher at 75, 72 and 26 per cent respectively, but it still lagged behind the level for straight couples.

Long Doan, lead author of the study which appears in the December issue of the American Sociological Review, said the findings revealed ongoing prejudices towards homosexuals, despite the big gains they have made in marriage equality.

"Gay rights cannot be summarily measured by public approval of same-sex marriage. Attitudes toward same-sex couples are more complex than that," the doctoral student told AFP via email. "Over 50 per cent of Americans support same-sex marriage," said Doan, whose research focuses on the ways that emotions can maintain inequality in society. "This is a remarkable increase in support from where it was several years ago, but what does that mean in terms of American ideals of equality?"

One twist that surprised Doan and his colleagues was that in some cases, homosexuals were even less approving of same-sex couples engaging in public displays of affection. For instance, 45 per cent of gay respondents thought it was acceptable for straight couples to French kiss, but 39 per cent believed gay men ought to do so as well. That might be due to fears in the gay community that such behavior might lead to harassment and hate crimes, said Doan.

Support among Americans for marriage equality has consistently been running at better than 50 per cent in successive Gallup polls since May 2012.