I've seen fairly compelling evidence of hormone level change in the Western world, though it seems unclear what the exact causes are. An accessible reference is

I've seen fairly compelling evidence of hormone level change in the Western world, though it seems unclear what the exact causes are. An accessible reference is Count Down -- https://www.goodreads.com/book/show/50892327-count-down https://www.goodreads.com/book/show/50892327-count-down