B.C.'s minister of children and family development has ordered a permanent end to a controversial sex testing program for young offenders after learning one of its government technicians was recently charged with sexual assault.

The penile plethysmography tests, or "phallometry," require boys as young as 13 in sex offence treatment programs to view pictures of nude and semi-clad children and listen to audio descriptions of forced sexual scenarios while their arousal levels are measured.

Minister Mary Polak said although the tests are intended to help develop treatments for sex offenders, the questionable nature of the procedure outweighs any potential benefits.

"Like most British Columbians, I was immediately concerned to learn of the testing being conducted involving young offenders, which is hard to fathom," she said in a statement sent to media Thursday.

Polak also said the ministry was forced to take swift action after discovering one of the government workers who conducts the tests was charged with sexual assault earlier this month. The charge is not work-related.

The BC Civil Liberties Association and the group Justice for Girls first raised concerns over the testing earlier this week.

B.C. Children's Representative Mary Ellen Turpel-Lafond is investigating the 25-year-old program to see if any of the participants were traumatized.