TORONTO - When Ryan and Ann Solomon got married, they knew they wanted to keep their family small. Ten years and two children later, the couple knows they made the right decision, given their situation.

With her husband a lieutenant-commander in the Royal Canadian Navy, and frequently away either training or at sea, much of the day-to-day parenting falls to Ann.

"We knew with Ryan's naval career that there were going to be a lot of periods of time when I would be by myself," said Solomon, the 39-year-old stay-at-home mother of Aidan, 9, and Ella, 6.

And when her husband's job kept him absent for nine of the first 12 months of Ella's life, that "really cemented it for me," she said. "Could I do it with throwing another baby in the mix? The answer to that was definitely, 'No way, Jose.'"

The Solomons' two-kid family is typical among their circle of friends in Ottawa. Indeed, couples with just one or two children have become the norm in Canada, part of a trend of steadily dwindling family size that has been going on since the early 1960s.

They're not alone, according to population projections Statistics Canada released Wednesday as part of the first release of data from the 2011 census. On its current trajectory, the numbers suggest, Canada's growth rate could be almost entirely dependent on immigration within 50 years.

Canada's birth rate is currently hovering around 1.67 children per woman, well below the minimum of 2.0 needed for natural population replacement.

So why are Canadians having so few children?

Ever since the postwar baby boom, there's been a drift towards smaller families, said Susan McDaniel, Canada Research Chair in Global Population and Life Course at the University of Lethbridge.

“And there's all kinds of reasons for that, but one of the major ones would be that we expect higher-quality children; we invest more time in them than we used to.”

That often means taking children to extracurricular activities and being involved in their school and homework, McDaniel said.

“So there's a lot of intensive parenting. And if you have a lot of kids, the intensity of the parenting cannot be as big, of course.”

With many women working full-time while raising young children, the issue of child care also comes into play, she said. “Because if you have to spend everything you earn to put the child in daycare or if you can't find a quality daycare and you're on a waiting list, it's going to make you think about having another child.”

Although Canada's birth rate has been stalled at roughly the same level for years, there's been a slight upward blip in the last decade, which McDaniel said is attributable to a cohort of older moms having their first child.

“The bump-up seems to be that a lot of couples have postponed child-bearing and then they get to the end of the child-bearing possibilities, or what they perceive as that, and they have a child later.”

That was the case for Shayna Jaymie Murray and husband Chris of Regina, who decided their family was complete with the birth of daughter Molly, now 20 months old.

“A lot of it has to do with my age and my husband's age,” said Murray, 39. “He's just a year younger than I am. We've only been married a couple of years and we decided sort of late in the game to have a family. So biologically it made sense to have just one.”

While the desire for small families is keeping the birth rate low, Canada doesn't differ much from other Western countries. The anomaly is the United States, where the national rate exceeds 2.0, though regional rates vary widely across the country.

“It's a mystery, we can't figure it out,” said McDaniel, noting that the U.S. has far fewer policies that encourage child-rearing — including access to public daycare and tax benefits — than Canada and other developed countries.

Religiosity could be a factor: Americans overall seem to be more influenced by religion than their relatively more secular northern neighbours. But that can't be the entire answer, McDaniel noted — Italy and Spain, primarily Catholic, have the lowest birth rates in Europe.

One theory making the rounds, based on research by Israeli economists, posits that the huge earnings gap between rich and poor Americans provides a pool of potential child-minders at the low end of the income spectrum, she said.

“Middle-class American women can... employ them to look after their children and therefore have the luxury of having more children.”

For Canada, expanding our numbers means depending on immigration, which accounts for two-thirds of population expansion. About 250,000 immigrants, most of them from China, India, Pakistan and the Philippines, are accepted into the country each year.

Some come from countries where economic, cultural and religious traditions have made larger families common, said Jeffrey Reitz, a professor of ethnic and immigration studies at the Munk School of Global Affairs at the University of Toronto.

“Immigrants from Pakistan, for example, have higher birth rates, so they bring more children with them,” Reitz said. “But the birth rate falls definitely after a period of time in Canada. In other words, they assimilate to our low-child mentality.

“The immigrants we get — highly educated people who are pursuing careers and want to advance themselves — their family procreation patterns are more or less the same as for the mainstream population and for the same reasons.”

And new Canadians' adoption of the birth-rate norm persists as they put down deeper roots in the country, McDaniel said. "The second- and third-generation immigrants are indistinguishable" from other Canadians.

Casting their eyes forward, demographers at Statistics Canada predict that in the coming decades, population expansion will become increasingly dependent on immigration as natural growth — births minus deaths — continues to slide. A huge part of that decline will result as the demographic bubble of baby boomers reach old age and begin dying off.

At the current rate, if nothing changes, immigration — currently responsible for 67 per cent of Canada's population growth — could account for 80 per cent of growth within the next 20 years, and nearly 100 per cent by the year 2061, Statistics Canada says.

So looking into the faces of Canadians 50 years hence, will the country look dramatically different?

“I don't see it really looking a lot different in the future than what it looks now,” McDaniel said. As older immigrants age and die, they will be replaced by new immigrants, changing and enriching the threads that make up the country's multicultural fabric.

“I don't see any great change to the face of Canada.”