Lots of variables are at play here, as well as nonlinear dynamics and feedback loops. To make matters worse, social factors are presumably involved (difficult to quantify and include in a model). Data on environmental pollutants and exposure levels are also basically non extant prior to the 90s. It's going to be as tough a puzzle to solv…
Lots of variables are at play here, as well as nonlinear dynamics and feedback loops. To make matters worse, social factors are presumably involved (difficult to quantify and include in a model). Data on environmental pollutants and exposure levels are also basically non extant prior to the 90s. It's going to be as tough a puzzle to solve as the question of anthropogenic climate change.
Some random thoughts/observations that may be of use:
Nutrition and caloric intake are one driving factor in determining the average age of menarche in a given population. Physiological stress can cause an individual woman to cease menstruation. (common in female distance runners)
Female hormonal cycles are altered by the presence/density of other females. Synchronization of cycles can occur in a house full of women, for example.
I was an adolescent in the early 90s. Girls went through puberty beginning in the 6th grade. It seemed nearly universal by 7th grade (age 12-13) For the Black population, this was shifted 1-2 years earlier.
For the Boys, it was similar to the girls, but shifted later by about 1 year.
As for the decrease in testosterone: The elimination of male spaces, especially work places must play a role. Competition/team work in male exclusive environments raises T levels in men, at least temporarily. 'Winning' competition (against other men) has an even greater effect. Possession of physical territory/successfully defending said territory has a similar effect. De-territorialisation has the opposite effect. What is mass immigration if not de-territorialisation of native male population? Atomisation is a characterized by, among other things, de territorialisation. No one 'owns' the local environment - we are all merely transient residents of the same crappy hotel.
Obesity lowers testosterone levels in men....and low t-levels cause men to gain fat mass. Not sure about the arrow of causation on this one. Might be bidirectional. Either way, the high carb, high sugar common diet must play a role at the population level.
Lots of variables are at play here, as well as nonlinear dynamics and feedback loops. To make matters worse, social factors are presumably involved (difficult to quantify and include in a model). Data on environmental pollutants and exposure levels are also basically non extant prior to the 90s. It's going to be as tough a puzzle to solve as the question of anthropogenic climate change.
Some random thoughts/observations that may be of use:
Nutrition and caloric intake are one driving factor in determining the average age of menarche in a given population. Physiological stress can cause an individual woman to cease menstruation. (common in female distance runners)
Female hormonal cycles are altered by the presence/density of other females. Synchronization of cycles can occur in a house full of women, for example.
I was an adolescent in the early 90s. Girls went through puberty beginning in the 6th grade. It seemed nearly universal by 7th grade (age 12-13) For the Black population, this was shifted 1-2 years earlier.
For the Boys, it was similar to the girls, but shifted later by about 1 year.
As for the decrease in testosterone: The elimination of male spaces, especially work places must play a role. Competition/team work in male exclusive environments raises T levels in men, at least temporarily. 'Winning' competition (against other men) has an even greater effect. Possession of physical territory/successfully defending said territory has a similar effect. De-territorialisation has the opposite effect. What is mass immigration if not de-territorialisation of native male population? Atomisation is a characterized by, among other things, de territorialisation. No one 'owns' the local environment - we are all merely transient residents of the same crappy hotel.
Obesity lowers testosterone levels in men....and low t-levels cause men to gain fat mass. Not sure about the arrow of causation on this one. Might be bidirectional. Either way, the high carb, high sugar common diet must play a role at the population level.