I do not believe that comparisons to our grandparents, great-grandparents, great-great-grandparents large families to modern day life is not valid.

For one thing, there were no reliable means of birth control available to them. A woman couldn't simply take a birth control pill, they didn't exist. Birth control as we know it now is a very new invention.

For another, our society was mainly an agricultural one back then. Parents owned a farm, and children worked on the farm. The more kids you had, the more work got done, the more pigs got slaughtered, eggs gathered, cows milked. Children added to your lifestyle, and were a means of support. The vast majority of people did not attend college, or get jobs away from the family farm. That is generally not the case now.

Also, the mortaility rate was higher. Vaccinations were not in existance, or not prevelant. Accidents, epidemics, poor nutrition, and common illness claimed many more young lives than they do now. It was simple math ... if a couple needed five strong young men to help run the family farm, they had better have about fifteen kids, knowing that about seven would be women who would marry and go to their husbands' farms, and at least three would die in childhood.