Edward Huxley, 70, from Cookham, Berkshire, told Mold Crown Court he was innocent and could not understand why the claims had been made.
The retired civil servant and six other men are charged with sexual abuse dating back to the 1970s and 80s.
The case is part of the Operation Pallial investigation into child abuse.
Mr Huxley told the court he did not go to gay bars in Wrexham and was not part of the gay scene in the town at the time.
He said he did not know any of his six co-defendants until he met them during the trial.
Mr Huxley said he was interested in men aged 25 to 45 and had previously been involved with people older than himself.
He said his current partner is 36 but told the jury he was not interested in anyone under the age of 25.
"Youngsters have never interested me. Neither conversationally or their bodies," he said.
When asked how the main complainant knew him, he said people would have known he was a civil servant and the civil service was based at the barracks in the town.
"I never took him to the barracks, I don't know him, I have never met him. He is a liar in these allegations against me," he told the jury.
The trial continues.
A former Met Police officer has told a court that a man who alleged he sexually abused him as a boy in Wrexham was a "compulsive liar".