'Chemical castration' trial aims to prevent child sexual abuse
Swedish scientists are recruiting unconvicted paedophiles for a new research project that aims to show that men at risk of sexually abusing children can be identified and treated before they target a victim.
The scientists are currently in the UK to promote crowdfunding support for their work.
Drugs have already been used in some institutions to suppress the urges of sex offenders.
The UK has its own pilot scheme, co-managed by NHS England, which began in 2008 at Whatton Prison in Nottinghamshire and is being rolled out across the country.
But the Swedish scientists are taking the controversial step of looking at whether men in the general population who are worried about their sexual urges can successfully be treated to prevent them committing crimes.
Alongside the "chemical castration" trial, they also hope to pinpoint "biomarkers" - tell-tale substances in the blood or brain wiring patterns - that mark out individuals who could pose a danger to children.
Dr Christoffer Rahm, from the Karolinska Institute in Stockholm, who heads the "Priotab" project, said the research was aimed at preventing abuse before it occurs.
Dr Rahm said a "handful" of men with paedophilic tendencies - none of whom had been convicted of any offence - had already been recruited by his team through a Swedish help line for people who fear their sexual appetites are out of control.
The study involves the use of degarelix, a prostate cancer drug that blocks signals from the brain that switch on production of testosterone.
The aim is to compare 30 men receiving the drug with 30 others given a "dummy" placebo treatment.
The scientists want to see if the drug can help the volunteers keep their sexual urges in check without causing unacceptable side effects.
The biomarker study, which was still at a "very early phase", would find out whether men who sexually abused children have any measurable traits that distinguish them from members of the general population.
Forensic psychiatrist Professor Donald Grubin, from the University of Newcastle, who is involved in the UK's Whatton Prison programme, said: "Typically we come in after an offence has been committed, and we try to pick up the pieces. It would be great if we could do something before that."