An old lawsuit claiming Republican Senate candidate Tom Coburn (search), an obstetrician, sterilized a woman without her consent and violated Medicaid rules has emerged as a major issue in his tightly contested race against Democratic Rep. Brad Carson (search).

Coburn said at a news conference Wednesday that he did nothing wrong and that his political opponents unearthed the lawsuit, which never went to trial, to hurt his candidacy.

"What you all are working from is an organized attempt to undermine my character," he said.

The lawsuit, first reported by Salon.com, was filed in December 1991 by a woman who was sterilized by Coburn more than a year earlier.

Angela Plummer, then 20, had come to him with an ectopic pregnancy, a dangerous condition in which an embryo was growing in her fallopian tube. He surgically removed the tube and tied off her other fallopian tube, leaving her sterile.

The woman alleged in her lawsuit that Coburn never received consent from her for tying off the healthy fallopian tube.

Coburn said that the woman had asked him for the sterilization procedure in previous instances and that he received oral consent. Medicaid did not cover sterilization procedures for women under 21.

Plummer, however, insisted again during an interview with The Associated Press Wednesday night that she hadn't discussed the procedure with Coburn in previous visits. She said she learned she had been sterilized during a checkup after her hospitalization.

"I was just kind of shocked," Plummer said. "It changed my life forever."

In a deposition filed in 1992, Coburn said he described the surgery to Medicaid as treatment for an ectopic pregnancy and did not describe the second procedure because if he had described both, Medicaid would not have covered it. He has said he was worried about the woman's bills.

In her deposition, the woman told the court that Coburn told her he had performed the ligation, but "you can't tell anyone because I will get in a lot of trouble for it."

Coburn said Wednesday there was no attempt to defraud Medicaid: "What I would say is go find Medicaid fraud on me. You won't find it.

"The fact is I never billed for" removing the healthy tube, he said. "Period. I know that, so therefore there can't be any Medicaid fraud."

He said no settlement was ever reached with the woman. She stopped pursuing the case, she said Wednesday, because she lost her attorney during the lengthy proceedings.

"What it is is, it's about the politics of personal attacks," Coburn said. "It's sad because it means because were not talking about the real issues."

"You're taking an unfounded accusation in a sleazy liberal dot-com and making it something real. Our country has got to be about more than a 14-year-old lawsuit that has no real factual basis," he said.

Coburn and Carson are locked in a tight race to succeed Republican Sen. Don Nickles (search). Coburn had been favored in early polls, but a new poll taken by Oklahoma City TV station KWTV indicated the two were in a dead heat.

Oklahoma is one of only a few states with open Senate seats this year, and the outcome could help decide which party controls the Senate.

Carson's campaign has denied being the source of the Salon article but said the allegations are serious.

"This is a very serious matter, and Tom Coburn will have to address questions about his past directly to the voters of Oklahoma," Carson spokesman Brad Luna said. "They obviously have a right to know the full story."

Coburn was known as a maverick and a conservative in Congress, and in 1997 helped lead a revolt against then-GOP House Speaker Newt Gingrich (search).

He has rankled Democrats with several recent comments. Last month, he referred to his race against Carson as "a battle for the culture of America" and "the battle of good vs. evil."

In a July interview with The Associated Press, Coburn said he favored the death penalty for "abortionists and other people who take life." He again raised Democrats' ire when he said economic development in Oklahoma was stymied by "a bunch of crapheads in Oklahoma City."

Jay Parmley, chairman of the Oklahoma Democratic Party, said serious questions are raised by Coburn's admission he did not disclose to Medicaid all of the medical procedures he performed.

"The only thing Tom Coburn is being smeared with is by a deposition where he swore on the Bible to tell the truth," Parmley said.