CHICAGO (AP) _ U.S. Rep. Mel Reynolds testified at his trial Monday that he had sexually explicit phone conversations with an underage campaign worker, but ``not one time ever in my life'' did they have sex.

``I am not guilty,'' Reynolds said at the end of four hours of questioning by defense attorney Sam Adam.

In a calm, even voice, Reynolds, 43, contested nearly every point made last week by his accuser, Beverly Heard, who testified she was 16 when Reynolds initiated their sexual relationship. He portrayed her as a troubled teen who became his partner in a phone sex relationship and later pressured him to give her money.

Reynolds stared straight ahead when Adam asked him if he had ever had sex with Heard. ``Not one time ever in my life,'' Reynolds replied.

Jurors frequently glanced in his direction and took notes as Reynolds testified that he was counseling a troubled teen by phone on numerous occasions in 1993 after she came to him for help. In May 1993, he said, their conversations turned sexual.

``Unfortunately in life, one makes mistakes, one is weak,'' the congressman said. ``It was probably the biggest mistake of my life. I began to have conversations with Beverly Heard, explicit conversations pertaining to sex.''

The Democrat is charged with aggravated criminal sexual abuse, criminal sexual assault, child pornography and obstruction of justice.

Reynolds said he was ``ashamed'' of the fantasy phone calls he had with Heard, but said he would never have sex with her because he did not want to give any sexually transmitted diseases to his wife, Marisol, with whom he was trying to have another child.

``That's why you had phone sex?'' Adam asked.

Reynolds said phone sex may be ``immoral'' and is a ``weakness'' but ``It's something that's safe.''

Heard, now 19, told prosecutors Reynolds initiated a sexual relationship that continued until she was 17. She said they began having sex within a couple of weeks after meeting Reynolds on the street outside a high school. He stopped her and told her she was pretty, she testified.

On the stand, Reynolds had a different story. He said he was campaigning and tried to greet as many people as he could. He said approached Heard and several other teens in June 1992 with the thought that they would tell their parents to vote for him.

Reynolds said shortly thereafter, Heard came to him seeking help getting into school and told him she was 18. He said he recommended her to an alternative high school in the city.

Reynolds testified Heard asked him for $15,000 in April 1994, after she returned from the U.S. Air Force, because she was living on the street. He said no. He said she again in a meeting the day before she went to police.

Reynolds denied ever seeing Heard with Sophia Green, a campaign volunteer. Heard testified the three had sex together several times.

In earlier testimony, Reynolds frequently glanced at the jury as he described how he picked cotton with his grandmother in rural Mound Bayou, Miss., and lived in poverty in Chicago as a child. He bowed his head and appeared to choke up when describing his grandmother's death on her birthday in 1976.

He told how he became a Rhodes scholar and went to Oxford and how he became involved in politics, working on the 1980 presidential campaign of Sen. Edward Kennedy, D-Mass.

Reynolds frequently made reference to his wife and three children.

Prosecutors have never provided any dates on which they allege Heard and Reynolds had sex, other than to say it was an ongoing relationship in 1992 and 1993.

Reynolds' attorneys had been split on calling him to testify. Some worried that Reynolds portraying himself as wrongly accused could be outweighed by his exposure to a potentially withering cross-examination from prosecutors.

Reynolds, who is black, contends he is the victim of racial bias on the part of a politically motivated white prosecutor. Prosecutors claim Reynolds has been trying to sabotage their case since he discovered last summer that he was under investigation.