A lot of comments here are pointing to specific causes such as microplastics and testosterone levels, prescriptions etc. Perhaps there's something to it, but gay/bi men specifically aren't slowing down, so this seems to be a uniquely straight issue [1]:
"In the post hoc analyses, an increase in sexual inactivity and having no sexual partners among men was observed in most sociodemographic subgroups but not among gay or bisexual participants..."
Medical advancements such as the availability of PrEP have been a boon to the gay community, and it's paired with frequent STD testing.
Gay men are exposed to the same environmental hazards, and also have smartphones/social media, so I'm not convinced that's what been slowing down their straight counterparts.
"In the post hoc analyses, an increase in sexual inactivity and having no sexual partners among men was observed in most sociodemographic subgroups but not among gay or bisexual participants..."
[1] https://jamanetwork.com/journals/jamanetworkopen/fullarticle...
Medical advancements such as the availability of PrEP have been a boon to the gay community, and it's paired with frequent STD testing.
Gay men are exposed to the same environmental hazards, and also have smartphones/social media, so I'm not convinced that's what been slowing down their straight counterparts.