Summary: There are many threats revealed by science. We obsess about some, such as climate change. Others we ignore, such as falling testosterone levels in men. This loss of our manliness might explain many things. America’s falling crime rates? The increased frequency of women filing for divorce (why hang around with a low-T beta?). Perhaps even our defeats in Iraq and Afghanistan, and the contempt of migrants for our borders.
CNN reports the news, with mockery: “Modern life rough on men“, 18 August 2011 — Opening…
“Didn’t men use to be more masculine? They were more ready to fight back, right? They walked with more swagger, and just did more things their way. Researchers can’t measure swagger – but they can measure testosterone, the male sex hormone most responsible for masculine behaviors – and studies show that testosterone levels in men have been on the decline for decades.
Two major studies have confirmed the phenomenon, one in U.S. men and another in Danish men. In the U.S. study, the total testosterone levels measured in men’s blood dropped approximately 22% between 1987 and 2004.
Of course testosterone levels drop as men get older, but what makes the study shocking is that men today actually have less testosterone than men used to have at the same age. The challenges to men’s health may not be limited to testosterone levels. The amount of sperm in ejaculated semen may be falling too. …”
There are other dimensions to the problem: “Why are men’s sperm rates falling?” by Dr. Phil Hammond in The Telegraph, 17 March 2014 — “Men’s sperm production is decreasing rapidly and the scientific community is struggling to find an explanation.”
Something is happening. Thousands of papers in the past few years examine the dynamics and effects of this powerful hormone. It responds to changes in a person’s social and physical environment. It influences men’s health and behavior in many ways.
Below the fold are summaries of eight papers, among the few that examine the changes during the past few decades in testosterone levels and male fertility. These longitudinal studies are of great value — but complex and expensive — and hence rare. They have been ignored by policy makers, but deserve attention. Lead poisoning helped bring down the Roman Empire. It was one of many factors in its decline, but one that they were unable to see (they knew about the danger of lead pipes, but not other sources of lead poisoning).