Somewhat interestingly, light exposure has a lot to do with onset of puberty. In our parents’ time, menarche for girls was around age 13-16, but now it’s usually much earlier.
I don’t think that is due to light. It has more to do with nutrition.
Or, it could be something like the seed oils that we consume. Soy has a lot of phyto-estrogen and was not really consumed as food in the U.S. until the early 1960s. Before that its approved use was glue for cardboard fabrication. (Quite step up. Then there is “Canola oil” modified rape seed oil previously used as marine lubricant and paint ingredient.)