In vitro fertilization, which Quebec provides free to infertile couples, may be another link in the spike in autism, a mysterious neurological disorder that affects cognition, communication and behaviour of toddlers and children.

 

The majority of children born using IVF do not have autism, and most children who have autism were not conceived using IVF, said Eric Fombonne, a professor of psychiatry at McGill University, and head of child psychiatry at The Montreal Children's Hospital.

 

But "the story is unfolding as we speak," said Fombonne, who has led autism epidemiological studies in a half-dozen countries and whose landmark research has shown that vaccines containing mercury are not among the causes of autism.

 

Fombonne was referring to studies including one from Assaf Harofeh Medical Center in Israel and another from Harvard School of Public Health in Boston presented at the International Meeting for Autism Research in Philadelphia last year.

 

The Israeli team's study suggested children conceived through IVF are three times more likely to suffer from mild to moderate autism.

 

The Harvard team found that autism was nearly twice as common among the children of women who were treated with ovulation-inducing drugs.

 

Every parent with a child that has autism spectrum disorder is asking the same thing: "What are the causes?"

 

"It may be the case that there is something there," Fombonne said of infertility treatments. "But it would apply to a very tiny proportion of the autistic population."

 

Fombonne is currently on a sabbatical at the renowned UC Davis MIND Institute in California.

 

Fombonne has been at the Autism Research Training program summer school, which aims to recruit top autism researchers across Canada. The week-long program at McGill University had 42 researchers from 14 universities in various fields, including genetics, brain imaging, neurology, education and psychology.

 

In terms of causes, there have been significant strides made in genetic research, Fombonne said, and scientists are considering a combination of various factors - genes, environment as well as early-prenatal environment - to explain rates as high as one child in 110 in North America with a form of autism disorder.

 

The debate now in assisted reproductive technologies, Fombonne said, is that the manipulation of sperm and egg may not actually change or mutate DNA, but this could lead to changes in ways genes function by silencing or modifying their expression.

 

But heritability probably plays a bigger role in autism and the link to IVF to date is far from clear, fertility specialists say.

 

According to a large, international, multi-site study led by researchers at the UC Davis MIND Institute, the risk that an infant with an older sibling with autism also will develop the disorder, previously estimated at between three per cent and 10 per cent, is now 19 per cent.

 

"Every year we have some medical condition that is associated with IVF - maybe. So we need to look into things without causing panic," explained Hananel Holzer, medical director of the McGill University Health Centre.

 

More studies are needed to tease out confounding factors, Holzer said. For example, is it the mother's age? Multiple pregnancies? Is the trait being passed on by someone who normally would not have conceived? Or is it the way the sperm and egg were manipulated in reproductive treatments?

 

"Infertility itself could be the risk factor," Holzer said.

 

The ideal study would look at the same population group, comparing those who had IVF with a control group that suffered from infertility issues but that conceived naturally, he said.

 

"The jury is still out," Holzer said, adding that a recent Danish study based on its national health registry found no added risk for autism disorders in children born with reproductive assistance, but the same study found a slightly higher risk with certain medications.

 

It is a given that some children will have the disorder because so many babies - millions - are born through IVF every year, he said.

 

"It's not that I'm trying to ignore the risk," Holzer said. "We have to look into things thoroughly and with responsibility."

 

The Quebec government's IVF mandate includes follow-up of long-term health consequences of women and their children born through reproductive assistance, Holzer noted.

 

"We really want to know the answers to these questions, and not only for autism," Holzer said.

 

Carl Laskin, president of the Canadian Fertility and Andrology Society and cofounder of a Toronto fertility clinic, said fertility clinicians are taking the IVF/autism connection "very seriously. But the numbers are small and the likelihood is small," Laskin said. "We can't comment on this being a real risk without further study and further collection of data.

 

"Our belief is that it should not discourage a couple from going forward."