Something’s wrong with our health.
Life expectancy has started reversing in the West. We have dramatically increasing rates of chronic diseases, mental health disorders, addiction, and suicide. You couldn’t be entirely blamed for having the pessimistic outlook I discussed last week in my notes from Schopenhauer.
One of the biggest emerging health issues is fertility. And unfortunately, this one gets talked about less because it’s not obvious, like obesity, and it’s often uncomfortable to discuss. Something is embarrassing about talking about fertility challenges or concerns. There’s a taboo around it.
And that taboo prevents us from realizing how big the problem is and how urgent it is for us to do something about it.
Whether you know it or not, you almost certainly know someone who is struggling with or has struggled with some form of fertility challenge. And this didn’t use to be the case. It has changed dramatically over the last fifty years, and not enough people are aware of it or talking about it.
So that’s what we’re going to talk about today.
As always, if you want to listen to the audio, subscribe to the Nat’s Notes podcast on YouTube, Spotify, Apple, Amazon, or anywhere else you listen to podcasts by searching “Nat’s Notes.”
Readwise is my absolute favorite reading tool. I use it pretty much every day, and if you like books, you should be using it too.
Readwise is your knowledge hub for everything you read. It can automatically import your highlights from Kindle, Instapaper, Pocket, and even scan your highlights from physical books.
Then anytime you want to reference your favorite parts of a book, you can immediately search them on Readwise, or in any note-taking app you connect your Readwise to like Notion.
They also recently launched the Readwise Reader which is what I use for reading all articles now, since it has a fantastic built-in highlighting tool that makes it easy to see anything you loved from past articles you read.
This is honestly the best tool out there for getting more out of everything you read. And they’re offering readers of Nat’s Notes a 2 month free trial to check it out. Just go to readwise.io/nat to get started.
Here are a few things I learned from the book. For more, be sure to check out the podcast episode!
Sperm counts and testosterone levels are both getting about 1% worse each year, and testicular cancer and erectile dysfunction are also increasing by about 1% per year.
The rate of adverse reproductive changes in males is increasing by about 1 percent per year. This includes the rates of declining sperm counts and testosterone levels, increasing rates of testicular cancer, and the projected worldwide increase in the prevalence of erectile dysfunction.
Between 1973 and 2011, sperm concentration (the number of sperm per milliliter of semen) dropped more than 52 percent among random men in Western countries; meanwhile, the total sperm count fell by more than 59 percent.
Miscarriage rates are increasing by about 1% per year.
On the female side of the equation, miscarriage rates are also increasing by about 1 percent per year.
The average 20-something woman today is less fertile than her grandmother was at 35.
As men get older, their sperm quality declines, and their children are more likely to have autism, schizophrenia, or down syndrome.
As men age, particularly as they reach the north side of forty, their sperm is more susceptible to mutation, which can increase the risk that their children will be born with disorders such as autism and schizophrenia or Down syndrome.
A man’s age can also increase his partner’s miscarriage risk.
A man's age also can affect his female partner's miscarriage risk. Studies suggest that for men ages forty and older, their partner has a 60 percent increased risk of experiencing miscarriage, compared to fathers under thirty; the risk appears to be stronger for first-trimester pregnancy losses, which are more likely to be chromosomally abnormal.
In-utero exposure to phthalates (via the mother’s exposure) can increase the risk of both autism and gender dysphoria.
One scientific theory suggests that in utero exposure to EDCS, particularly phthalates, which can lower a fetus's exposure to testosterone, may play a role; these chemicals have been associated with an increased risk of autism spectrum disorders (ASDS) in males. Interestingly, ASD and gender dysphoria, two seemingly unrelated conditions, occur together more often than expected. Another theory is that EDCS can interfere with complex biochemical pathways in the brain in ways affect how a person associates with his or her physiological sex at may that birth or expresses their gender through behavior, either of which may result in gender dysphoria.
In-utero exposure to pesticides is also associated with greater risk for genital malformations in males.
Research has found an association between high prenatal exposures to EDCS-for instance, éxposures to pesticides or phthalates-and a higher risk of external genital malformations in male newborns. And researchers at the University if a parent had occupational of North Texas have explored the physiological pathways through which EDCS can influence sexual differentiation in humans.
Using marijuana once per week is associated with a 29% lower sperm count.
A 2015 study from Denmark found that regularly smoking marijuana more than once a week was associated with a 29 percent lower sperm count; even worse, men ages eighteen to twenty-eight who used marijuana more than once a week as well as other recreational drugs reduced their total sperm count by 55 percent. Among men undergoing fertility evaluation as a precursor to assisted reproduction, those who used large quantities of marijuana were four times more likely to have poor swimmers, and moderate users were nearly three and a half times more likely to have abnormally shaped sperm.
Tylenol use has been shown to cause sperm abnormalities and make it harder to get pregnant.
Tylenol has been shown to cause sperm abnormalities, including DNA fragmentation, and to increase the time it takes to achieve a pregnancy; moreover, taking high doses of Tylenol can alter the shape of sperm in ways that can compromise their fertilizing capabilities.
Using SSRIs reduces sperm concentration and motility, and increases the number of abnormal sperm.
At every age, women are twice as likely to take antidepressants as men, and the use of these medications increased 64 percent from 1999 to 2014 for both genders. And-are you detecting a pattern?-the use of SSRIS (selective serotonin reuptake inhibitors), which are prescribed primarily for depression or anxiety, reduces sperm concentration and motility and increases the percentage of abnormal sperm.
Men’s sexual health is a leading health indicator, men diagnosed with infertility had 30% higher risk of diabetes and 48% higher risk of heart disease.
In a 2016 study of some thirteen thousand men who'd been diagnosed with male factor infertility, researchers found that men with low sperm concentrations had a 30 percent increased risk of developing diabetes and a 48 percent increased risk of developing ischemic heart disease, compared to men without the infertility diagnosis.
Men who get more than seven hours a week of moderate exercise have 43% higher sperm concentrations.
Men who get more than seven hours week per of moderate to vigorous physical activity have 43 percent higher sperm concentrations than those who exercise an hour or less per week.
Men with high levels of work stress had a much higher chance of low sperm concentration.
When researchers in China examined the effects of work stress on semen quality among 384 men, they found that men with high levels of work stress had a greater chance of having swimmers classified below the WHO's threshold for “normal" sperm concentration and total sperm count than those with low work stress.
There are quite a few lifestyle things you can do to improve your fertility, and dramatically decrease your risk of your fertility being impacted by your environment (covered in the podcast!)
That’s all for this week! I hope you learned something, and I’ll be back with another great book to share for Nat’s Notes next week.