Researchers in Finland have found that having a boy, historically speaking, shortens a mother’s life expectancy by a statistically significant amount. Their study, which looked at Finnish villagers in pre-industrial Scandinavia, showed that a woman’s risk of death increased by seven percent per year for each son born. By investigating parish records for individuals in eight parishes who lived during the seventeenth to mid-twentieth centuries, “they found that if a woman in these communities was 37 years old at the time of having her last child, her life expectancy would vary depending on the sex of her children.”
It remains to be determined whether biological or environmental factors are most responsible for the effect of boys on their mothers’s lifespans. Lead author of the study, Samuli Helle of the University of Turku in Finland said: “We need more data, such as how many sons versus daughters helped in everyday tasks, what age they actually started to work outside the home and so on.” Similar studies have found that boys take more of a toll on their mother biologically because they are heavier at birth than girls. And a few studies have found that women expend more energy in producing breast milk for boys.
Photo credit: Shutterstock.com