When Friedrich Nietzsche declared "That which does not kill us makes us stronger", he probably did not have parenthood in mind.
Yet a new study suggests that despite the sleepless nights, incessant worry and financial headaches that children bring, they also increase longevity.
In fact, fathers can expect to live nearly two years longer than childless men, while mothers gain an extra 18 months.
Scientists do not believe the effect is biological, but rather the result of a loving support network, which is crucial in later life when something as simple as a fall can be fatal.
People with a close-knit family are also generally encouraged by their loved ones to visit the doctor, stay active and take care of themselves.
Previous studies have found that loneliness or losing a partner in later life can hasten death, but this is the first large study to show that children have a protective effect.
Dr Karin Modig of the epidemiology unit at the Institute of Environmental Medicine in Karolinska Institute, Stockholm, Sweden, which carried out the study, said: "Having children is associated with increased longevity, particularly in an absolute sense in old age.
"Support from adult children to ageing parents may be of importance for parental health and longevity.
"At old age, the stress of parenthood is likely to be lower and instead, parents can benefit from social support from their children.
"In addition, parents have on average more healthful behaviours than childless individuals."
To find out if parenthood might help stave off death in older age, the researchers studied the records of nearly 1.5million people who were born as early as 1911, looking at when they died and whether they had children.
After taking account of influential factors such as educational achievement and deprivation, the results showed that life expectancy was higher among those who had children.
The findings contradict previous studies that suggest, for women at least, children shorten the life span by diverting resources from physical maintenance to reproduction. In poor communities, having four or more children has been shown to shorten life span by 3.5 years.
In Sweden and the other Nordic countries, there is an overall trend of increasing levels of childlessness across birth cohorts
But the new study found that mothers lived on average to 84.6 compared with women without children, whose life expectancy was 83.1.
The difference was even more striking for fathers, whose life expectancy was 80.2 compared with 78.4 for childless men.
The gap in death risks between the two groups also rose with increasing age, and was larger for men than it was for women.
At age 60 the difference in the one-year risk of death was 0.06% among men and 0.16% among women. By the age of 90 these differences had risen to 1.47% among men and to 1.10% among women.
The associations were even greater among unmarried men, where the chance of dying earlier doubled for those who did not have children.
The researchers suggest that unmarried men might rely more heavily on their children in the absence of a partner.
They are also likely to be less well educated, whereas unmarried women tend to be more educated.
Modig said: "Our finding that the association grew stronger when parents became older is further in agreement with research suggesting that childless people face support deficits only towards the end of life.
"In Sweden and the other Nordic countries, there is an overall trend of increasing levels of childlessness across birth cohorts.
"It may therefore be valuable to improve our understanding of how childlessness is linked to health and survival chances in old age."