Most scientific studies are false. Meta analyses have low credibility in general, due to subjective inclusion/exclusion, differing methods, etc. Experts usually have an axe to grind (eg funding).
Still, this one seems straightforward on the sperm count issue, but causation and so on leave a lot to be researched.
The Epoch Times: Global Sperm Counts Dropped More than 50% in Recent Decades, 2 Main Causes: Experts
The global sperm counts have fallen more than 50 percent in the last 46 years, and the drop is accelerating, according to a recent meta-analysis.
...Why Sperm Count Matters
Sperm count is not only a parameter of a man’s sperm quality but also an important indicator of his overall health.
“Low sperm count hurts your health directly,” said Swan. “Men with low sperm count and women who have reproductive problems have a shorter life expectancy. They die younger. There are quite a few studies on this.”
[WIND: correlation is not causation and there is no causal link established. If this “expert’ is being quoted correctly, it’s shocking to see the use of a logical fallacy used as a scientific claim]
A 2018 study found that low sperm count was associated with metabolic alterations, cardiovascular risk, and low bone mass. Men with low sperm count also had a higher risk of developing diabetes, heart disease, and stroke.
[WIND: correlation is not causation; it seems that all of these issues stem from an underlying cause, whether it is chemical-based or lifestyle or both]
Even though no causal link has been established between sperm count and infertility, lower sperm count decreases the likelihood to conceive.
You can see that in almost every country in the world, fertility has been declining. And the rate of decline is exactly the rate of decline in sperm count. It’s about 1 percent per year,” said Swan.
[WIND: correlation is not causation, and maybe it is more social than anyting. And maybe not]
... Reduce Chemical Exposure
Swan said a major source of chemicals is food, especially processed food.
“When you process food, you milk a cow, or you make spaghetti sauce, you’re passing it through plastic,” said Swan.
Plastic contains phthalates—a large group of chemicals that are often used to make plastics flexible. Phthalates are not chemically bound to plastic. “So they leave the plastic, and they go into the food, which goes into our body.”
A 2018 systematic review found “robust evidence of an association between DEHP and DBP [two types phthalates] exposure and male reproductive outcomes,” including reduced semen quality and a longer time to achieving pregnancy.
“Another thing you can do is worry about the plastic that’s in your kitchen in various forms or something related, which is Teflon, nonstick, PFAS chemical,” Swan said.
“Try to use glass, china, metal to the extent possible. And, of course, never microwave in plastic. That’s a really bad, bad thing to do.”
...The Harm May Pass on to Future Generations
Chemical exposure and unhealthy lifestyle habits could compromise fetal development and further impact the child’s reproductive health and overall health, or even the child’s next generation, warned Swan.
“If you alter the development of the fetus in a profound way, that is never going to change, and it’s not ever going to affect just one system,” said Swan.
“If you alter, say, testosterone, which is what I study the most, in early pregnancy, you’re not only going to affect reproductive health, you’re going to affect neurodevelopment—the brain also needs the right amount of testosterone. You’re going to affect the entire body when you interfere with hormones in early pregnancy.”
[WIND: does this explain the explosion in the number of feminized beta males? Or maybe it’s government schools doing it too.]
In her book, Swan refers to a 2017 study that found some phthalates were associated with changes in sperm DNA that resulted in poorer embryo quality and a lower chance of implantation. The phthalates affected the genes that can influence a male baby’s reproductive development and eventually a grown man’s semen quality and fertility status.
Women are not immune to the effects, either. For example, a grown man who smokes cigarettes typically experiences a 15 percent decline in his sperm count, but he can recover if he quits the habit. However, a mother smoking during pregnancy may lead to her grown son losing his sperm count by up to 40 percent. Even worse, it is irreversible.
WIND: I strongly favor avoiding plastics, processed foods, etc. The idea that a few hundred chemicals many of which mimic hormones are “safe” is ludicrous, especially in combination. And, follow the money, no industry willingly changes its ways unless it increase profits. And the idea that our beloved FDA is not asleep at the switch and corrupt is for children and idiots.
Could social factors be more of the issue? Including mental illness (depression), stress, etc.
Populations in some large countries are predicted to implode (eg China and it’s disastrous one-child policy), resulting in major social upheaval when a too-small population of young people cannot support a too-large population of elders. This challenge faces most of the developed countries of the world. It already is hitting some countries hard, like Japan. It has profound implications over the next 10-30 years—not very far off. And it’s not solvable, unlike the climate change farce (hint: nuclear power whatever you think about its credibility).
Here in the USA, the only thing that might save us from a population implosion is the open border policy and the minimally-managed illegal entry of about about 7 million unvetted people in two years. Could what looks like an invasion turn out to have the silver lining of compensating for anotherwise declining US population?