ATLANTA - In the winter of 2003, Genarlow Wilson's future seemed bright.

An honor student, standout athlete and homecoming king, the 17-year-old was preparing for the SAT he hoped would pave the way to college. A New Year's Eve party fueled by alcohol, marijuana and sex at a Douglas County hotel changed all that.

Mr. Wilson, now 21, is serving 10 years without the possibility of parole after a jury found him guilty of aggravated child molestation for having consensual oral sex with a 15-year-old girl that night.

The tough sentence has sparked protest, even from members of the jury that convicted him and the author of the 1995 law that put him behind bars.

"The law was designed to protect kids against really, really bad people doing very bad things," said the sponsor, former state Rep. Matt Towery, a Republican. "It was never intended to put kids in jail for oral sex."

Today, Mr. Wilson's legal team will again try to free him as a Monroe County Court hears a claim that Mr. Wilson's constitutional rights are being violated.

"This is a good kid who doesn't belong in prison," said Mr. Wilson's appellate lawyer B.J. Bernstein, of Atlanta.

Mr. Bernstein compared the case to the recent rape case involving Duke University lacrosse players. Prosecutors in both cases overreached, Mr. Bernstein said.

Mr. Wilson has now served more than 27 months in prison and his plight has become something of a cause clebr. That's largely because of the odd legal loophole that ensnared him.

If Mr. Wilson had had sexual intercourse with a teen, he would have fallen under Georgia's "Romeo and Juliet" exception. But under the law in 2003, oral sex for teens still constituted aggravated child molestation and carried a mandatory sentence.

Mr. Wilson's case shows how a law designed to go after child sex predators can have unintended consequences and criminalize consensual sexual activity between teens, said Karen Worthington, the director of the Barton Child Law and Policy Clinic at Emory Law School.

Georgia lawmakers in 2006 changed the law to make consensual oral sex between teens a misdemeanor, punishable by a maximum of one year behind bars. Offenders also would not have to register as a sex offender, as Mr. Wilson will be required to.

But the state's top court ruled that change couldn't be applied retroactively to Mr. Wilson's case. An attempt earlier this year to pass a bill that would provide Mr. Wilson a remedy stalled.

The effort was complicated by a homemade videotape showing the New Year's Eve party. On the tape, a 15-year-old girl can be seen performing oral sex on Mr. Wilson. It also shows Mr. Wilson and other male partygoers having sexual intercourse with a 17-year-old girl.

Prosecutors argued the 17-year-old was semiconscious and not capable of consent. A jury that watched the tape disagreed and acquitted Mr. Wilson of the rape charges.

The five other male partygoers took plea deals. Mr. Wilson's case was the only one that went to trial.