People who believe businesses should be able to deny services to same-sex couples aren't necessarily citing religious reasons for discriminating, a new study by Indiana University sociologists has found.

Instead, many simply believe businesses should be able to deny services to whomever they want — even though that violates civil rights laws that protect certain classes of people.

"I thought it would be about religious freedom, but it's not," said IU sociology professor Brian Powell, the lead author of the study.

The study, which surveyed 2,000 people across the U.S., could lend some insights into the national debate over religious freedom and gay rights. The conflict is on display with the U.S. Supreme Court's consideration of a case involving a Christian baker who refused to make a wedding cake for a same-sex couple.

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Slightly more than half of those surveyed said they supported a business denying wedding services to a same-sex couple, whether the business cited religious opposition to same-sex marriage or non-religious reasons.

The study also asked about interracial couples — a comparison drawn by both sides of the debate.

About two-fifths of people supported businesses denying wedding services to interracial couples, the study found.

"The word 'anyone' is a key word for denial of services," Powell said. Those who support denying services largely said business should be able to deny services to anyone.

Those who oppose it, however, often used the word "everyone" — saying businesses should treat everyone the same.

The study showed that people largely regarded the decision to serve or not serve same-sex couples as a business practice, Powell said, rather than a religious liberty issue.

Those who supported denying services often used the words "freedom" or "choice" in explaining their rationales, while those who opposed it described "discrimination."

There was also a distinction between people who believe businesses are "private" and those who say they are operating in the "public" sphere, Powell said.

Some respondents suggested that the free market would deal with discriminatory businesses. Denying services to certain customers might be appalling, they told researchers, but businesses should have the right to do it — just as people should have the right to picket and boycott such businesses.

"It's the idea that people who treat different groups differently ultimately will be penalized," Powell said. "Ultimately, the market would wipe out discriminatory businesses."

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Respondents also did not tend to invoke freedom of speech issues, he added. They stayed away from the argument that a business's services could be considered art, and so to compel them to create a product that conflicted with religious beliefs would violate their freedom of expression.

The study found demographic trends among those more likely to support denying wedding services to same-sex couples: Men were more likely than women; heterosexual people more likely than gay, lesbian or bisexual people; whites more likely than blacks; and older people more likely than younger people.

The more conservative or religious people were, the more likely they were to support denying wedding services to same-sex couples, Powell said. Ninety percent of Republican respondents said businesses should have that right.

The study also found that people were more likely to side with self-employed individuals that denied services than corporations. That presents a contrast to the U.S. Supreme Court's 2014 ruling in the Hobby Lobby case, which extended individual rights to corporations by recognizing the religious beliefs of closely-held corporations like Hobby Lobby.

The study was published in Science Advances, a publication of the American Association for the Advancement of Science.

Call IndyStar reporter Stephanie Wang at (317) 444-6184. Follow her on Twitter: @stephaniewang.