All sons know that we get more flak than daughters. Does "You've taken years off my life" or "Why can't you be more like your sister?" sound familiar?
Unfortunately, a new study, published this week in Science, shows that these refrains may hold an uncomfortable truth. In preindustrial times, sons really did have adverse effects on mothers. And worse news still for male children is that daughters helped to offset the negative effects of their male siblings.
Scientists studying Finnish church records have discovered that there was a biological cost to having sons -- each son took an average of 34 weeks off a mother's life. The effect is cumulative: more sons = shorter life span.