Two parents in St. John's want the Newfoundland and Labrador government to make screening for cystic fibrosis mandatory for newborns.

John and Gillian Bennett learned their son, John, had CF — a fatal genetic disease — when he was 75 days old, after weeks of fear and anxiety, including watching the boy not gain weight in his earliest days.

John Bennett became an advocate on cystic fibrosis after his baby was diagnosed with the genetic disease. (CBC )

"I understand that there may be a cost associated with doing this, but you cannot put a cost on a child's life," John Bennett told CBC News.

"If one person gets helped by newborn screening, at the end of the day, I think that's a good thing."

Bennett said an early intervention can help a child dramatically, and that he is aware of some children reaching years before they are diagnosed.

Bennett's exposure to the problems of cystic fibrosis led him to get involved Cystic Fibrosis Canada. He now serves as a regional director.

Ontario and some western provinces provide screening for newborns, although Newfoundland and Labrador does not.

The Bennetts noticed a difference in their baby within one day of starting medication. Now two, the boy is lively, has gained weight and plays actively with his parents.

Gillian Bennett said screening — which is done through a simple blood test — could help new parents take appropriate action.

"It was actually kind of a relief to know exactly what was going on, because for me, for two and a half months, part of me felt like I was doing something wrong," she said.

Her husband agreed.

"It was two and a half months of uncertainty, is what it was," he said. "We were afraid to see a set of scales because we didn't want to know if he had lost weight again."