Is there an ideal age gap between siblings?

There are the "get it over with" supporters who sacrifice five years of sleep and prefer to have kids close in age. Chances are they won't remember the insanity of it all when their kids are seven and eight, happily playing together somewhere other than underfoot.

The "only one kid in diapers" camp believes in getting a year or more of good sleep (and saving money on nappies) before diving in again. There are drawbacks to waiting, of course, like having to store all your baby gear.

"With the one-year maternity leave, it didn't make sense to immediately have another baby, because I'd just be back at work when I got pregnant again," says Erin MacDonald, a 37-year-old mother of two (who are spaced three years and three months apart).

Co-workers may view you as a ticking time bomb of second-time gestation. Which may be an argument for having your kids close together — you take the career hit once, then go back at it full-force when your family is complete.

Maren Kubik, a 30-year-old mother from Calgary, worries her daughter will miss one-on-one time with mom and dad when a baby brother or sister enters the picture. "When another kid comes along, your time isn't totally devoted to your first child," she says.

"In some ways [sibling relationships] are a natural laboratory for learning how to express yourself," says Nina Howe, a professor of early childhood and elementary education at Concordia University in Montreal. "How do you learn to play and take turns? How do you care for the feelings of another person, so that, hopefully, they'll do the same for you? It's a very rich relationship."

"An age gap between one and three years is probably optimal, in the sense that the older one is not going to have any memories of being an only child," says Howe. The kids grow up thinking they've always had a sibling because they can't remember when they didn't. Their concept of family doesn't shift very much when the new baby arrives.

"It doesn't mean there won't be any temper tantrums and regress. But generally those things fade after a few months."

There's a four-year age difference between David Yiptong's daughters, and the Calgary engineer sees it as largely positive. In practical terms, it was great: No need to buy another crib or infant car seat and no need for the dreaded double stroller that makes it look like you're driving a minivan through Starbucks.

Now that his girls are five and nine, they're starting to interact more. They may not always want to do the same thing but Yiptong isn't convinced it's because of the years between them. Even if they were only one or two years apart, his eldest would still want to read and his youngest would still want to play.

According to a recent Statistics Canada study, about 40 percent of Canadian families are in the "have them close together" camp, spacing their children one to three years apart. On the flip side, it seems about 37 percent of families believe in catching up on some sleep before adding another kid to the household; their children were born three to five years apart.