Illinois and Hawaii are the latest states to join a list of fourteen others, and Washington, D.C., in legalizing gay marriage.
"Sometimes social change creates change in the law, but sometimes the law can create social change."
Author Jason Pierceson is revising his latest book on same-sex marriage because of recent changes in history since the book hit stores in March.
"I think, clearly, in a state like Illinois, the law responded to changes in public opinion."
A recent Gallup Poll suggests Dr. Pierceson is right. The numbers show support for same-sex marriage has doubled in less than 20-years. According to Reuters, five states added the laws in 2013 alone.
"The biggest shift and support of gay rights is coming from the younger generations."
Still, there are 34 states without marriage equality, but even supporters say the trend might slow down.
"I don't think you'll see a bunch of states saying, 'oh, they did this in Illinois, now we're ready to do it too,' because, even in Illinois, it's contested. It's highly contested."
Sociologist professor Tiffani Saunders says universal acceptance is unlikely.
"We'll never see, you know, 100 percent acceptance."
Evidence of that can be found in religious and conservative groups which don't seem to be budging on their beliefs.
"If you are, in a sense, you have the intention of trying to promote something that is gravely sinful, then you are putting your salvation in jeopardy."
Illinois' same-sex marriage law doesn't take effect until June 1, 2014. Lawmakers could look at a bill to bump up the effective date when they return for their spring session in January.
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