Mother Nature Mostly Hates Men: Mortality Science!
By Heath Shive
Back in 2000, psychiatrist Sebastian Kraemer wrote a paper for The British Medical Journal entitled “The Fragile Male.” It created quite a stir.
Men have a shorter average life expectancy than women. But Kraemer thought a male was inherently more likely to die from the very beginning – even in his mother’s womb!
Kraemer argued that many obstetric maladies – perinatal diseases, deformities, stillbirths, etc. – afflicted males much more than females. At birth, the ratio of males to females is roughly 105 to 100. Kraemer believed that the ratio at conception started about 120 to 100 – and then Nature started to cull off males.
To the science!
But That Changed
Recently, a study published in Proceedings of the National Academy of Sciences showed that fetal mortality isn't so simple.
The scientists analyzed 140,000 embryos (conceived by IVF or other technologies) in the first days after conception. Male embryos were more likely to be abnormal and so die a week or two after conception. At first, male mortality is higher.
But data from about 800,000 amniocentesis tests showed that between weeks 10-15 more female embryos are miscarried.
In the third trimester, male mortality rates accelerate.
But overall, female fetus mortality rates were slightly higher.
To be more specific, there would seem to be “different windows of vulnerability” for males and females during development.
Mortality by Gene-Based Behavior
After birth, male mortality rates exceed female rates – because of the consequences of risk-taking behavior. Evolutionary psychologists – like Glenn Geher and Scott Kaufman in their book Mating Intelligence Unleashed – believed that such risk-taking behaviors were intrinsic to men, written on their DNA, to display strength and virility to women.
Behaviors affect vulnerability to disease. Zhang et al (1995) showed men were more likely to die from most diseases (“total cardiovascular disease and cancer”).
In the U.S., homicide victims are 3 times more likely to be male than female. According to the American Foundation for Suicide Prevention, men are 3 times more likely to commit suicide.
Whether from genes or gene-based behavior, from the womb to the tomb, men seem to be….more expendable to Nature.
According to a nursery rhyme, little boys are made of “snips and snails and puppy-dogs' tails.” Whatever men are made of…it’s perilous stuff.
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Kraemer S. (2000). The fragile male. British Medical Journal, 321, 1609–1612.
Geher, Glenn and Kaufman, Scott. Mating Intelligence Unleashed: The Role of the Mind in Sex, Dating, and Love. Oxford University Press, 2013.
Lawlor D., Ebrahim S., Smith G. (2001). Sex matters: Secular and geographical trends in sex difference in coronary heart disease mortality. British Medical Journal, 323, 541-545.
Orzack, Steven Hecht, J. William Stubblefield, Viatcheslav R. Akmaev, Pere Colls, Santiago Munné, Thomas Scholl, David Steinsaltz, and James E. Zuckerman. The human sex ratio from conception to birth. PNAS April 21, 2015. 112 (16) E2102-E2111
Zhang X., Sasaki S., Kesteloot H. (1995). The sex ratio of mortality and its secular trends. International Journal of Epidemiology, 24, 720-729.
Hello! My name is Heath Shive, content manager at ScholarFox. I'll be the author of most of the blog posts. I'm a former geologist and currently a freelance writer. The world is complex and seemingly crazy. Good! Because when you love to learn, you'll never be bored.