Sons are tough on their mothers. In many ways. One is the least expected of all. Sons hurt a mother’s life span itself! After going through Finnish church records from two centuries ago, Virpi Lummaa of the University of Sheffield in England has come to a conclusion that having a son can reduce a mother’s life span by an average of 34 weeks.
The culprit is the boy’s weight (typically heavier) and also Testosterone.
“Testosterone can compromise your immune system; it can affect your health,” Lummaa says, and the mothers of sons proved especially susceptible to endemic infectious disease, such as tuberculosis.
Also, the boys hurt their siblings as well. Not only are the younger sisters of boys likely to be lighter but have a host of other issues:
This phenomenon is particularly evident in twins where one is male and the other is female. Of 754 twins born between 1734 and 1888 in five towns in rural Finland, girls from mixed-gender pairs proved 25 percent less likely to have children, had at least two fewer children, and were about 15 percent less likely to marry than those born with a sister. This brotherly influence remained the same regardless of social class or other cultural factors and even endured if the male twin died within three months of birth, leaving the female twin to be reared as an only child.