Aromatase is an enzyme in fatty tissue that converts testosterone to estrogen. That's why fat men often have breast buds - they have more aromatase than lean men. Men are getting fatter = more aromatase = lower testosterone.
Disagree with most of the comments, but love all the ideas people are putting forward!
Going from most plausible to least plausible claims:
1. Lower T is one of the drivers of obesity, and lower T is caused by some mixture of obesogenic diets, declining physical activity, and pro-female cultural pressures.
2. The study on testicular suggests testicular cancer is most likely diet and hormone related. India has a notoriously low meat intake, and smaller, more effeminate, men. Lower T, lower growth hormone (lower heights), and probably lower IGF-1 (due to less meat) all contribute to their lack of testicular cancer.
3. Porn somehow decreases T levels by giving men depression, or through suppressing their effort in mate-seeking. The immunosuppression idea doesn't make sense to me as surely that would lead to more infections? Yet precisely the opposite has happened over time. In fact, declining infections has been speculated to be a driver of obesity, as less time fighting off infection generally means lower body temperatures, which means less energy expenditure in the form of heat.
4. The lobster man was right to recognise the significance of the pill in changing society. There's a few studies suggesting that some forms of female contraception decrease women's preferences for physical masculinity, and heightens their focus on other factors (What kind of dad will he be? What kind of job does he have? Is his family wealthy?). It is also possible that lower T for men might be somewhat correlated with income, since lower T probably makes you more likely to do better in school, and more capable of adapting to an increasingly feminine work environment.
So perhaps birth control has led to more men with a low T phenotype reproducing, due to them having better jobs (and wealthier families?) on average.
Tbh, I think people generally underrate the pill as an explanation for a lot of things. We are doing this massive experiment of putting lots exogenous sex hormones in women, and there is probably no free lunch there. For example, if you're a guy taking T for a long time, your body eventually loses its ability to create T itself, so you have to stay on it for life just to remain normal. Obviously, T has many behavioural effects too, so it seems probable to me that fucking with womens' hormones for years (especially during puberty) is going to cause some pretty significant changes.
It's the diet. Look for testosterone to plummet with the introduction of sugar and industrially-processed food. Same negative effects on dentition. See Weston Price and vitamin K.
Another issue is mutational load caused by fewer sperm in competition. Going from 200 million sperm to 50 million may still get the job done, but there are fewer good sperm to choose from, meaning that the resulting offspring may be less fit and with greater mutational factors.
"I don't really have any other good ideas aside from positing nefarious environmental toxins, which is never a good starting point."
why would that not be a good starting point when those toxins are ubiquitous and known to disrupt hormone function?
without a doubt endocrine disruptors are the primary cause of testosterone collapse. Flame retardants, bisphenols, phthalates, parabens, pesticides, PFAS, microplastics, synthetic estrogens, etc. etc. etc. Chemical diversity and chemical burden is orders of magnitude higher than generations past. Exposures in the womb cause disorders of sexual development. This is well established for BPA and phthalates. Puberty is also being stunted. Sperm production in adults..
It's interesting that most of the leadership on the far right are half mexican. Nick Fuentes, Voxday Popoli, Christopher Langan, Dick Masterson to name a few. I suspect it's not because of higher testosterone but because of higher androgen sensitivity. Unfortunately, most of the people coming over the border illegally aren't mexican, but aztec or guatemalan. These people usually reside in the south of mexico while the actual mexicans are in the north.
In my opinion, the reason europeans have declining testosterone is because the royalty of past empires imposed strict laws effectively neutering their population. Then WWI and WWII. Now it's women's rights effectively selecting for more easily controllable males. Despite what may be portrayed in media, women don't like a strong man that will control them.
I’ve noticed my entire adult life that men are getting more effeminate (I’m 55, female....born that way) I also noticed that young women look like linebackers....broad shoulders, covered in tattoos and very aggressive. I raised my sons in a world that tells them everything they love is bad. I am proud to say they turned out exceptional. Their father was a psychopath and has no interest in anyone but himself. They were blessed that he stayed away.
Perhaps there's another bulletpoint you can add to the list, an increase in the frequency of hypospadias:
"The international total prevalence of hypospadias for all years was 20.9 (95% confidence interval: 19.2–22.6) per 10 000 births. The prevalence for each program ranged from 2.1 to 39.1 per 10 000 births. The international total prevalence increased 1.6 times during the study period, by 0.25 cases per 10 000 births per year (p < 0.05). When analyzed separately, there were increasing trends for first-, second-, and third-degree hypospadias during the early 1990s to mid-2000s. The majority of programs (61.9%) had a significantly increasing trend during many of the years evaluated. Limitations include known differences in data collection methods across programs."
People are getting fatter and fat is estrogenic.
Aromatase is an enzyme in fatty tissue that converts testosterone to estrogen. That's why fat men often have breast buds - they have more aromatase than lean men. Men are getting fatter = more aromatase = lower testosterone.
Eigher that, or it's the hormones in the chicken!
Disagree with most of the comments, but love all the ideas people are putting forward!
Going from most plausible to least plausible claims:
1. Lower T is one of the drivers of obesity, and lower T is caused by some mixture of obesogenic diets, declining physical activity, and pro-female cultural pressures.
2. The study on testicular suggests testicular cancer is most likely diet and hormone related. India has a notoriously low meat intake, and smaller, more effeminate, men. Lower T, lower growth hormone (lower heights), and probably lower IGF-1 (due to less meat) all contribute to their lack of testicular cancer.
3. Porn somehow decreases T levels by giving men depression, or through suppressing their effort in mate-seeking. The immunosuppression idea doesn't make sense to me as surely that would lead to more infections? Yet precisely the opposite has happened over time. In fact, declining infections has been speculated to be a driver of obesity, as less time fighting off infection generally means lower body temperatures, which means less energy expenditure in the form of heat.
4. The lobster man was right to recognise the significance of the pill in changing society. There's a few studies suggesting that some forms of female contraception decrease women's preferences for physical masculinity, and heightens their focus on other factors (What kind of dad will he be? What kind of job does he have? Is his family wealthy?). It is also possible that lower T for men might be somewhat correlated with income, since lower T probably makes you more likely to do better in school, and more capable of adapting to an increasingly feminine work environment.
So perhaps birth control has led to more men with a low T phenotype reproducing, due to them having better jobs (and wealthier families?) on average.
Tbh, I think people generally underrate the pill as an explanation for a lot of things. We are doing this massive experiment of putting lots exogenous sex hormones in women, and there is probably no free lunch there. For example, if you're a guy taking T for a long time, your body eventually loses its ability to create T itself, so you have to stay on it for life just to remain normal. Obviously, T has many behavioural effects too, so it seems probable to me that fucking with womens' hormones for years (especially during puberty) is going to cause some pretty significant changes.
It's the diet. Look for testosterone to plummet with the introduction of sugar and industrially-processed food. Same negative effects on dentition. See Weston Price and vitamin K.
My guess is that there are several factors:
1. Toxicity from known endocrine disruptors (eg plastics) and poisonous food sources (seed oils)
2. Sedentary lifestyles - exertion raises t
3. Obesity - fat tissue is estrogenic
4. Social - getting nagged by women all the time with no escape can't be helping anyone's t levels
Which is dominant, hard to say. Maybe this could be teased out with a dataset large enough to make the appropriate comparisons.
Another issue is mutational load caused by fewer sperm in competition. Going from 200 million sperm to 50 million may still get the job done, but there are fewer good sperm to choose from, meaning that the resulting offspring may be less fit and with greater mutational factors.
"I don't really have any other good ideas aside from positing nefarious environmental toxins, which is never a good starting point."
why would that not be a good starting point when those toxins are ubiquitous and known to disrupt hormone function?
without a doubt endocrine disruptors are the primary cause of testosterone collapse. Flame retardants, bisphenols, phthalates, parabens, pesticides, PFAS, microplastics, synthetic estrogens, etc. etc. etc. Chemical diversity and chemical burden is orders of magnitude higher than generations past. Exposures in the womb cause disorders of sexual development. This is well established for BPA and phthalates. Puberty is also being stunted. Sperm production in adults..
It's chemical.
This is so obviously caused by excessive ejaculation due to porn and looser sexual norms.
Just throwing this into the ring.
https://scopeblog.stanford.edu/2023/02/14/is-an-increase-in-penile-length-cause-for-concern/
Why are environmental toxins a bad hypothesis?
Phtalates are estrogenic. Many such cases. There are more hormonal distruptors in our blood these days.
It's interesting that most of the leadership on the far right are half mexican. Nick Fuentes, Voxday Popoli, Christopher Langan, Dick Masterson to name a few. I suspect it's not because of higher testosterone but because of higher androgen sensitivity. Unfortunately, most of the people coming over the border illegally aren't mexican, but aztec or guatemalan. These people usually reside in the south of mexico while the actual mexicans are in the north.
In my opinion, the reason europeans have declining testosterone is because the royalty of past empires imposed strict laws effectively neutering their population. Then WWI and WWII. Now it's women's rights effectively selecting for more easily controllable males. Despite what may be portrayed in media, women don't like a strong man that will control them.
I’ve noticed my entire adult life that men are getting more effeminate (I’m 55, female....born that way) I also noticed that young women look like linebackers....broad shoulders, covered in tattoos and very aggressive. I raised my sons in a world that tells them everything they love is bad. I am proud to say they turned out exceptional. Their father was a psychopath and has no interest in anyone but himself. They were blessed that he stayed away.
"and it must be an environmental factor because genetic selection is favoring manliness"
Hmm, selection favors people who have a lot of children, but fertility is declining.
Culture is strong. But hard to imagine that cultural factors could have a big impact on testosterone levels.
Perhaps there's another bulletpoint you can add to the list, an increase in the frequency of hypospadias:
"The international total prevalence of hypospadias for all years was 20.9 (95% confidence interval: 19.2–22.6) per 10 000 births. The prevalence for each program ranged from 2.1 to 39.1 per 10 000 births. The international total prevalence increased 1.6 times during the study period, by 0.25 cases per 10 000 births per year (p < 0.05). When analyzed separately, there were increasing trends for first-, second-, and third-degree hypospadias during the early 1990s to mid-2000s. The majority of programs (61.9%) had a significantly increasing trend during many of the years evaluated. Limitations include known differences in data collection methods across programs."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7265200/
Maybe there's also an increasing in cryptorchidism:
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(84)92697-7/fulltext
If all these have a common cause it seems to be pre-natal and not, say, obesity, tight pants and nagging ladies.
Electrostatic charge from tight and synthetic material underwear lowers T -- a relatively new development compared to pants