It's likely a correlation between:

Amount of processed foods eaten

Amount of pesticides on and in foods

Amount of environmental synthetic birth control hormones

Emphasis on high carb, low protein, low healthy fats consumed

Amount of seed oils consumed

Lack of running around outside growing up

Houses being too well sealed/never experiencing hot and cold extremes

Poor sleeping habits

Being fat (effects aside from poor eating habits and bad foods, it's really bad for people)

Lack of fitness

Too much medication

Lack of healthy gut biome

Not eating traditional fermented foods

Too much alcohol

Too much cannabis

Too little motivation toward actual physical sexual relationships (probably from much too young exposure to porn and all the beauty influencers)

Too much social media leading to dopamine addiction

Et cetera.