Drew Legary, right, a male nurse at the Alberta Children's Hospital, has been charged with sexually assaulting two children who were under his care. (CBC/Facebook)

A male nurse has been charged with sexually assaulting two patients at the Alberta Children's Hospital in Calgary.

Drew Robert Legary, 42, of Calgary, is charged with two counts of sexual interference of a child under 16 years and two counts of sexual assault.

Calgary police said a 13-year-old boy made a complaint in September 2011.

Police then learned of a second victim, an 11-year-old boy, who they believe was sexually assaulted in August 2010.

Both were patients in the care of the man, who was working as a nurse. Both incidents were alleged to have happened while the children were under the nurse's care.

The father of the 13-year-old said the thing that upsets him the most is that there was a second victim.

“What I didn’t know was that it happened to another kid, this is my biggest hurt right now,” he said.

The man said his son has been scarred for life.

“I felt very much betrayed, because I trusted the hospital, I trusted the male nurse, who had built a rapport for two days with my son and I,” said the father.

Det. Stephen Johnston of the Calgary police’s child abuse unit said he was satisfied during the investigation that there were no other victims at risk.

There were no third-party witnesses to either assault, said Johnston.

"[Both victims] are certainly shaken by what has happened and certainly experienced something that no child should ever endure," he said.

Legary has been on leave from the hospital since the allegations surfaced, according to Alberta Health Services.