Opposition to gay marriage has increased since the summer and a narrow majority of Americans also oppose allowing gays and lesbians to enter legal agreements that fall short of marriage. Moreover, despite the overall rise in tolerance toward gays since the 1980s, many Americans remain highly critical of homosexuals ­ and religious belief is a major factor in these attitudes.

A 55% majority believes it is a sin to engage in homosexual behavior, and that view is much more prevalent among those who have a high level of religious commitment (76%). About half of all Americans have an unfavorable opinion of gay men (50%) and lesbians (48%), but highly religious people are much more likely to hold negative views.

Religiosity is clearly a factor in the recent rise in opposition to gay marriage. Overall, nearly six-in-ten Americans (59%) oppose gay marriage, up from 53% in July. But those with a high level of religious commitment now oppose gay marriage by more than six-to-one (80%-12%), a significant shift since July (71%-21%). The public is somewhat more supportive of legal agreements for gays that provide many of the same benefits of marriage; still, a 51% majority also opposes this step.

A new national survey of 1,515 adults, conducted Oct. 15-19 by the Pew Research Center for The People & The Press and the Pew Forum on Religion and Public Life finds that homosexuality in general ­ not merely the contentious issue of gay marriage ­ is a major topic in churches and other houses of worship. In fact, clergy are nearly as likely to address homosexuality from the pulpit as they are to speak out about abortion or prayer in school, say people who attend church regularly.

The clergy in evangelical churches focus considerably more attention on homosexuality ­ and address it far more negatively ­ than do ministers and priests in other denominations. Two-thirds of evangelical Protestants who attend church services at least once a month say their ministers speak out on homosexual issues, compared with only about half of Catholics (49%) and just a third of mainline Protestants (33%). And compared with others who attend services where homosexuality is discussed, substantially more evangelicals (86%) say the message they are receiving is that homosexuality should be discouraged, not accepted.

The poll finds that people who hear clergy talk about homosexuality are more likely to have highly unfavorable views of gays and lesbians. This is especially the case in evangelical churches. Fully 55% of evangelicals who attend services where the issue of homosexuality is addressed have very unfavorable views of homosexuals. This compares with 28% of those who regularly attend services in non-evangelical Protestant and Catholic churches where clergy discuss homosexuality. Similarly, evangelicals who hear sermons on this issue are much more apt than others to believe that gays and lesbians can change their sexual orientation and to view homosexuality as a threat to the country.

The survey underscores how the debate over societal acceptance of homosexuality has shifted since the mid-1980s. The public has moved decisively in the direction of tolerance on many questions; in particular, discrimination against homosexuals is now widely opposed. This is seen in long-term trends in surveys conducted by the Pew Research Center and by the Gallup Organization. And the current survey shows that a majority of Americans (54%) feel that gay and lesbian couples can be as good parents as heterosexual couples.

Yet as public attention has turned to questions of gay marriage ­ and as homosexuals have become far more visible in society and the entertainment media ­ there have been some signs of a backlash. Roughly three-in-ten Americans (31%) say greater acceptance of gays would be a bad thing for the country, up from 23% in a 2000 survey conducted by the Kaiser Family Foundation. And nearly half the public (48%) thinks the entertainment media present too many gay themes and characters, compared with 37% in the same 2000 survey.

In light of this changing climate of opinion, the importance of gay marriage in the 2004 elections remains unclear. But there is evidence that this issue could become problematic for the Democratic presidential nominee. Voters who support President Bush are largely of one mind on this issue: More than three-quarters (78%) of voters who favor the president’s reelection in 2004 oppose gay marriage; more than half (53%) strongly oppose the idea. But voters who prefer to see a Democrat elected in 2004 are divided ­ 46% favor gay marriage, 48% oppose. A substantial minority of these Democratic-leaning voters strongly oppose gay marriage (25%).

The survey also shows that Americans remain deeply divided over the essential cause and nature of homosexuality. A 42% plurality believes that being a homosexual “is just the way that some people prefer to live,” no change from a Los Angeles Times survey conducted in 1985. But there has been a rise in the percentage who say homosexuality is “something that people are born with” ­ from 20% in the Times survey to 30% currently. The public also is split on the question of whether a gay person’s sexual orientation can be changed ­ 42% say it can, the same number disagrees.

Still, most Americans say they are comfortable interacting socially with homosexuals. Just one-in-five say they are uncomfortable around homosexuals, while 76% say they do not mind being around gays. Highly religious white evangelicals are more likely to say they are uncomfortable being around homosexuals ­ a third express that view. Even so, six-in-ten in that group say it does not bother them to be around homosexuals.