A student brought this article to my attention:
A biodemographical study of life span in pre-industrial Finland has provided evidence that boys are impose a longevity cost to their mothers (but not their fathers). In other words, the more boys a woman has, the shorter her lifespan. It has been posited that early reproductive effort might come at the cost of later survival and decreased later reproduction. This study is in accord with those ideas of reproductive tradeoffs. Why boys should be costlier than girls, though, is less clear. Here is the study: A trade-off between having many sons and shorter maternal post-reproductive survival in pre-industrial Finland (not open access).
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Joe Alcock
Emergency Physician, Educator, Researcher, interested in the microbiome, evolution, and medicine
EvolutionMedicine 
Aha ~ just as I’d expected; it is what I’ve been telling my (two) sons for years. Not necessarily good news for me (maternal grandparents were Finnish-Swedes). p.s. Am delighted I ran across this blog (today), as I’ve many immediate family members in medicine, including an ER doc (adjunct professor UT, Houston), cousin affiliated with WHO in China, Oncology in Boston, a 91 yr old uncle (one of the original preventative health researchers out of U of MN Medical School) who claims to need little sleep (he forgets he’s a cat napper), etc. Have always been fascinated by evolutionary biology and medicine. ciao ~ j macheledt