Peter Whitmore, who was sentenced to life in prison this week for the kidnapping and sexual assault of two Prairie boys, has asked to be chemically castrated, according to reports.

The Winnipeg Free Press reported that Whitmore, 36, has written a letter to prison officials seeking the procedure.

It involves drugs that can permanently remove hormonal drives and the ability to create testosterone.

In 2005, Whitmore agreed to be chemically castrated following his release from jail, but officials couldn't find a doctor who would take Whitmore as a patient, his former lawyer Dan Brodsky told CBC News on Friday.

Brodsky said he hopes Whitmore will be able to get the drugs he needs this time.

"What it will do is it will give him a trial on the medication. No doctor's going to say the medication will work. Some people can't take the medication for a variety of different reasons," he said. "And in a case like Mr. Whitmore's, I don't think you should wonder about whether the medication is going to work, or not."

On Monday, Whitmore entered guilty pleas in a Regina court on charges stemming from events in the summer of 2006 involving a 10-year-old from Saskatchewan and a 14-year-old from Manitoba. The charges included sexual assault causing bodily harm and other sex offences, kidnapping, making death threats and a child pornography offence.

Whitmore won't be eligible for parole for seven years.

However, Roz Prober, a spokeswoman for Beyond Borders, a children's protection advocacy group, questioned Whitmore's motives in requesting chemical castration.

"Peter Whitmore is highly manipulative," she said. "This is just a ploy that he's going to use to try to get out of prison and pull the wool over the parole board's eyes."

Prober believes the Crown made a mistake with a plea bargain deal for guilty pleas in exchange for not proceeding with a dangerous offender application. People declared dangerous offenders are subject to an indefinite prison term. The Crown has argued the life sentence achieves essentially the same thing and spares the victims from testifying.

Brodsky noted Whitmore wants to be free at some point and Whitmore expects taking the medication will help his case.

Long before the 2006 incidents, Whitmore had a history of child sex offences.

In 1993, Whitmore was convicted of abduction and sexual offences involving four boys in Ontario, and served 16 months in custody.

Just nine days after he was released, he took an eight-year-old girl from Guelph, Ont., to Toronto. He received a 56-month sentence for a sex offence involving the girl.