When it comes to children being raised in homes where their parents produced drugs, medically speaking, in most cases the kids are all right, suggests a Canadian study.

While it doesn't condone home-grown illicit substances, the research from the Motherisk Program at the Hospital for Sick Children in Toronto goes on to question the frequent seizure of children from those homes as it found most kids to be healthy and free of drug exposure symptoms.

The study, published in the online edition of the Journal of Pediatrics, is being cautiously received by police and child welfare agencies which say the good news on the medical front is only one part of a larger picture where additional risks to the child still exist.

Motherisk examined 75 children in Ontario's York Region between 2006 and 2010. The research was prompted by a request from the region's police and children's aid society after a spike in kids found at suburban drug production units.

While 32 per cent of the children had hair tests that came back positive for the presence of illicit substances, the majority of kids who were studied had no clinical symptoms related to the drugs.

Hair follicle tests can be positive long after exposure to drugs and can indicate the environmental presence of drugs or chemicals used to make them. The positive test doesn't mean that the child has been damaged by the drug.

Additionally, the study said there were fewer health problems among the children examined than those in the general Canadian population.

"We clearly found ourselves that the kids are doing well," study author Dr. Gideon Koren told The Canadian Press on Tuesday. "Which brings the question, is it healthy to separate them from parents?"

Koren said the research suggests not all in-home drug operations can be considered the same and the decision to remove a child must be made on a case-by-case basis.

He added that most children examined were sad at being separated from their parents and were not doing well in school at the time, but were nonetheless largely healthy and free of drugs themselves.

"You cannot equate parents producing illegal drugs as necessarily people who are dangerous for their kids," he said, adding that children who came from such homes were usually well taken care of before being taken away.

There were also very few cases in which the parents were drug users themselves, or where the Children's Aid Society was aware of the family before the home was raided, he said.

One important distinction that emerged in the study, however, was that children who grew up in homes running methamphetamine labs were in poorer health.

The York Region's Children's Aid Society -- which saw an "explosion" of children coming into its care with the suburban grow-op boom of the early 2000s -- said Koren's study is a valuable one, but must also be placed into context.

Director Patrick Lake said every effort is now made to place a child with extended family, friends or even a teacher, but if a parent is arrested for producing drugs, the society usually has to step in.

"Obviously we can't leave children in the home unattended, so we still are automatically involved in a lot of these cases," he said.

The society now also takes a more "customized care" approach to every case, made possible by changes in 2007 to Ontario's Child and Family Services Act.

The positive bill of health aside, Lake said other risk factors like the presence of firearms in a home, potential domestic violence, the level of secrecy that needs to be maintained by the children and risky living conditions must also be considered.

He also points out that in most cases the kids are returned to their families in anywhere from a few months to a few days.

"It's not like we've got this warehouse of kids," said Lake. "These kids are going back home once we've been able to deal with the other risk factors involved in the home."

The York Regional Police had a similar response, saying the research was encouraging from a medical perspective but only dealt with one piece of a larger puzzle.

"Whether there's drugs present or not, we need to be concerned," said Deputy Police Chief Bruce Herridge. "'Is this child in need of care?' That determination cannot be left solely to whether they're medically well or not."

Herridge said the presence of children found in these operations is evaluated based on a number of factors such as how long they had been there, if they'd been left alone near dangerous chemicals and their level of knowledge about the drugs.

"I think it's useful information," he said of the study. "But it's not to the point where in a police investigation we would say, 'Oh there's kids here but who cares, there's no medical ill-effects of them being here, so we shouldn't be concerned about them.' I don't think any one looks at a child from one dimension."