Good news moms-of-many! New research suggests the number of children a woman bears influences the rate at which her body ages, and -- perhaps surprisingly -- the more babies she has, the longer she could live.

The study by Simon Fraser University found that women who give birth to more surviving children exhibited longer telomeres, the protective tips found at the end of each DNA strand which are indicative of cellular aging. Longer telomeres are integral to cell replication and are associated with longevity.

One might think that since more kids means more aggravation, stress, and running around, women with many children might live shorter lives. But interestingly, the study findings contradict life history theory which predicts that producing a higher number of offspring accelerates the pace of biological aging.

Why? Hormones, researchers think.

"The slower pace of telomere shortening found in the study participants who have more children, however, may be attributed to the dramatic increase in estrogen, a hormone produced during pregnancy," said Pablo Nepomnaschy the health sciences professor who led the study and who also spearheads the Maternal and Child Health Laboratory at the SFU Faculty of Health Sciences. "Estrogen functions as a potent antioxidant that protects cells against telomere shortening."

The social environment that the study participants live in may also influence the relationship between their reproductive efforts and the pace of aging. "The women we followed over the course of the study were from natural fertility populations where mothers who bear numerous children receive more social support from their relatives and friends," explained Nepomnaschy. "Greater support leads to an increase in the amount of metabolic energy that can be allocated to tissue maintenance, thereby slowing down the process of aging."