CHICAGO (AP) -- If prosecutors can prove a videotape features R. Kelly and an underage girl, the R&B superstar's child pornography trial could end with him receiving a lengthy prison sentence.

But prosecutors will run into defense challenges at every turn. Kelly, 41, denies he's the man on the tape. The 23-year-old woman prosecutors say was a minor at the time of the taping denies she's the girl on the video. Defense attorneys may also contend the girl, whoever she was, wasn't a minor at all.

How prosecutors intend to eliminate a reasonable doubt about those challenges may become clearer Tuesday as opening statements were to begin in a trial that has been delayed repeatedly since the tape was mailed to the Chicago Sun-Times in 2002. The newspaper turned it over to authorities, and Kelly was indicted later that year.

Kelly, with an entourage in tow, arrived at the Cook County Criminal Courthouse about 90 minutes before opening statements were scheduled to begin. He wore a navy pinstriped suit and blue-and-orange striped tie, and his hair was in corn rows.

Prosecutors say the tape was made between Jan. 1, 1998, and Nov. 1, 2000. Kelly is accused of videotaping himself about 10 years ago having sex with a girl as young as 13 years old.

The singer, who has pleaded not guilty, faces up to 15 years if convicted.

Kelly won a Grammy Award in 1997 for the gospel-tinged "I Believe I Can Fly," and is also known for such songs as "Bump N' Grind," "Ignition" and "Trapped in the Closet," a multipart saga about the sexual secrets of a lively and ever-expanding cast of characters.

Jury selection finished last week with prosecutors and defense attorneys accusing each other of trying to stack the panel along racial lines. Eight jurors are white and four are black.

The panel includes a Baptist preacher's wife, a young woman who said she was once raped, and a business executive who said during jury selection he had believed Kelly was guilty.

Despite intense media attention on the case, Judge Vincent Gaughan has vowed not to let the trial sink into a celebrity circus. He has demanded the respect of reporters, even holding up a plastic bag during a hearing Friday and saying it held pieces of chewed gum he had collected under the rows where they sat during jury selection.

"Don't stick gum on the benches," he said. "Actually, it's a crime."

The defense is led by Ed Genson, highly sought by defendants for his persuasive powers with jurors. The gray-bearded Genson suffers from a neurological disorder that can make him walk as if he suffers from a severe hip injury, and he often uses a motorized scooter. He's known to adopt a gasping, stammering air that masks the wiles of a shrewd tactician.

Shauna Boliker is expected to take the lead for the prosecution. The birth of her third child last year was one reason for the delays in the trial - among others were a case of appendicitis for Kelly and the judge's fall from a ladder.

Boliker has prosecuted several high-profile cases, including that of a Catholic priest who pleaded guilty last year to abusing five boys.

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