In a fight to deny double paid parental leaves to an Ottawa couple who have twins, the federal government is citing a study that challenges a motherhood assumption: Longer maternity leaves, the research concludes, do not improve early child development.
The government is appealing a ruling that granted both Christian Martin and Paula Critchley full parental leave benefits to care for their baby girls, arguing that the decision contravened federal employment insurance rules.
But what worries the parents' lawyer and the opposition Liberals is one study in a package of evidence introduced by government lawyers. While some of the reports support expanded time off, the paper found that doubling maternity leave to one year did not lead to gains in child development.
Never mind the mommy wars over staying at home versus rejoining the work force, the question of whether longer parental leaves have tangible advantages for children is the subject of great debate among sociologists and economists.
"The research that has been done is inconsistent at best, and it's largely because it's very complex and challenging to assess," said Donna Lero, a professor of family relations and applied nutrition at the University of Guelph who has studied parental leave.
To Mr. Martin, however, there was no debate on the benefits of him and his wife both taking time off to look after Athena and Lucie, who were born five weeks premature in April, 2009. While Ms. Critchley received maternity benefits for a year, Mr. Martin took eight months leave but hasn't yet received EI payments because of the lengthy appeal process.
"We had a lot of work to do with respect to taking care of them. They needed a lot of support," said the 34-year-old researcher, adding that the girls are now 21 months old, healthy and "very vocal."
Studies that support extended leaves have found that mothers who work during a child's first year generally stop breastfeeding sooner, and that their children tend to have behavioural problems and slightly lower scores in cognitive development and academic achievement. Others conclude that longer leaves improve mother-child attachment, reduce maternal stress and lower infant mortality rates.
On the opposite side of the debate, researchers have found that longer maternity leaves do not improve children's development, and can hinder women's advancement at work and erode gender equality.
Part of the reason for the lack of consensus is that teasing out the effects of parental time off on children's well-being involves evaluating a host of interconnected variables, including infant health, the quality of child care, parenting styles, work force opportunities, income, gender equality and families' support systems.
Measurable benefits aside, however, governments extend parental leaves for other reasons, including boosting fertility rates, pleasing voters and keeping women in the work force.
Since Jean Chrétien's Liberal government doubled parental leave in late 2000, parents have embraced the opportunity to stay home longer. The length of time most mothers took off jumped to between nine and 12 months in 2001 from five to six months the previous year, according to Statistics Canada. And 10 per cent of fathers claimed or planned to claim parental benefits in the first year of the new policy, triple the previous level. Under current rules, mothers receive 15 weeks of pregnancy leave and both parents can share a maximum of 35 weeks of parental benefits of up to $468 per week.
However, for Kevin Milligan, a University of British Columbia economics professor, the main assumption underlying extended parental leaves - that staying home longer is better for children - cried out for further scrutiny.
Prof. Milligan and Michael Baker, a University of Toronto economics and public policy professor, did the study that found longer parental leaves did not have a positive impact on child development. They used data from youngsters born before and after maternity leave was expanded, including markers such as temperament, achievement of milestones, and motor and social development.
"The question to ask is what kind of bang are we getting for our buck there," he said. "If the only thing you're looking at was the impact on child development, then it would be a hard case to make."
However, they also found that back when women could take only six months of maternity leave, babies largely were left with relatives, nannies or neighbours - not daycares - when their mothers returned to work.
Still, the government's reference to their paper, which was published last year in The Journal of Human Resources, has raised concerns among some observers that the Conservatives are less than committed to year-long maternity leaves.
"The fact that they're citing this study in this court case does mean that they better clarify with Canadians in a hurry is there a secret agenda to cut this key social program that parents across the country count on," said Carolyn Bennett, a Toronto Liberal MP.
The government's lawyers, Dale Noseworthy and Renée Darisse, referred interview requests to Anna Maddison, a Human Resources and Skills Development spokeswoman, who wrote
in an e-mail: "It is not appropriate for us to comment due to ongoing legal proceedings."
But in asking that the research be entered into evidence for the appeal, scheduled for next week in Toronto, Ms. Noseworthy and Ms. Darisse wrote in a letter earlier this month: "Please note, however, that we take no position on the validity of the study."