For most people large, tight families who do just about everything en masse is the stuff of legend, or reality TV shows. But as the oldest of ten children I live with it every day, this article for example was interrupted to rescue a precious stuffed bunny from the new puppy, and mediate who got to wear the princess dress.

So you can imagine the results when two such families, with eight and ten children respectively, are brought together by a courtship and later engagement. Actually, unless you were brought up in a similar family you probably can’t. Suffice to say that it includes insane amounts of food, folk dancing, practical jokes involving balloons, chicken slaughtering (honest!), and a home-grown film company to make a documentary of the whole relationship. But the slaughter of innocent chickens has not been the only result of this engagement.

For my brother (19) it has also meant that adolescence, and an era of low responsibility, is officially over. While a little while ago he could afford to hesitate about committing to a particular career, now getting, and keeping, a stable, good paying job as a tradesman’s apprentice has suddenly become of vital importance. After all, if he looses his job he is going to have a very hard time convincing his fiancee’s parents that a 2011 wedding is a good idea. A reliable car has become more than a luxury, and he suddenly has no interest in spending money on computers or other non essentials. Marriage has been a great motivator.

I know my brother isn’t alone among young people when it comes to falling in love, but while it has driven him to grow up, complete milestones in education and employment, and save money, for many people the pressures that created those achievements are lacking. Last week the Institute for Marriage and Family Canada released a report on the causes of delayed adulthood. One of those, they suggest, may be co-habitation.

It would be very simplistic to suggest that co-habitation is the only reason for delayed adulthood, and in fact it may be more of a symptom than a cause. But it does rate some thoughtful consideration. If few people were willing to live together before marriage, we could reasonably expect marriage rates to climb dramatically, most people aren’t willing to wait forever for intimate companionship. And with an increase in marriage rates, young adults would be highly motivated to “get going” with their lives. While Mom and Dad may be willing to subsidize your apartment while you are going to college, with or without a clear notion of who your roommate is, they are probably less likely to do so once you get married.

Without a doubt there are myriad reasons for the lengthened period between adolescence and independent adulthood that we are seeing today, but cohabitation cannot be helping. When my brother gets married next year he will have to assume all the responsibilities of an adult, and he has risen to that challenge. But what if that challenge didn’t exist? We have been asking, “Why won’t they grow up?” Maybe we should be asking, “Why should they grow up?”