(CNN) Jacob Moore went to visit Larry Nassar, a gymnastics doctor and family friend, after gymnastics practice one day in April 2016, for what he thought would be treatment for his ailing shoulder.

But in Nassar's basement, the doctor pulled down Moore's pants and administered acupuncture to his genital area, claiming that it would help his shoulder, Moore said. As he did so, Nassar spoke to another young female gymnast in the treatment room about whether she had seen a man's body part before, Moore's attorney said.

The encounter left Moore feeling "quite uncomfortable" and did nothing to help his injured shoulder, which later required surgery, Moore said in a press conference on Monday.

Moore, now a freshman gymnast at the University of Michigan, became the first man to accuse Nassar of sexual abuse when he joined a civil federal suit against Nassar and others associated with the scandal last week.

Moore, now 18, said he decided to come forward with his story after he watched his sister and nearly 200 other girls and women testify at Nassar's criminal sentencing earlier this year. No men came forward to say they were abused.

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