Of course, some advertisers might shy away from him, especially if they or their consumers tend to be conservative. But experts also said the U.S. is changing; more than half of Americans support marriage for same-sex couples, according to a recent Quinnipiac University poll.
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"Lately there have been some commercials, even Super Bowl commercials, where you saw gay couples… the tide is turning," Dorfman said.
While brands that have a history of being gay-friendly would certainly be interested in working with Sam, Dorfman said companies that have not typically gotten involved in gay-rights issues also might come calling.
"It even could be companies like Apple or one of the tech companies," he said. "It could be fashion, where there's already a little more gay acceptance, possibly grooming products. It could be soft drink commercials, it could be fast food… It's pretty wide open."
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When NBA player Jason Collins said he was gay last year, sponsor Nike issued a statement in support of Collins, and Dorfman said it wouldn't be surprising if the company was interested in Sam, as well. "Nike has always been a kind of trendsetter and cutting edge," he said. "I think a company like Nike would likely be an ideal company to sign him."
Bob Dilenschneider, founder and principal of PR and branding firm The Dilenschneider Group, predicted Sam's coming-out could open the door to other gay athletes. "I think this is going to bring out more gay players in the NFL," he said.
—By Martha C. White of NBC News