Surely it cannot be that hard to control for weight when doing a study on testosterone amounts in the body? i.e. we have half the sperm, but that's overall - do people who have a healthy weight also have half the sperm?

These are the problems that arise when everyone and their moms start talking about scientific studies this way.

We don't have enough information. We don't know how they collected their data, we don't know how they analyzed it, even if we did most of us don't know enough to judge those methods etc.

Most "science" is honestly worthless crap done by some random person mainly because they want a PhD or are trying to pad their publication count. They look for some arbitrary thing to test, half-assedly design a study, collect as little data as they can get away with, do a little p-hacking and such to make sure the results are significant (otherwise the time was wasted) then they publish.

Have you considered that you are simply listing two symptoms together instead of identifying cause and effect?

The average American consumes 23% more calories per day in 2010 then in 1970[1] and does 100 calories less physical activity per day in their occupation since 1960[2].

[1] https://www.pewresearch.org/short-reads/2016/12/13/whats-on-...

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102055/

Have you considered that this is the _symptom_?