Why more girls are experiencing earlier puberty

You have to be careful with averages. For many hundreds of years, the average was not so different from today 12-14. However, this is skewed by the wealthy v. poor. Those that were fed well, and led gentle lives had higher body fat, started their periods earlier, the poor had less to eat and worked harder, and therefore had very low body fat, and started their periods later.

At least here in the USA where many chemicals have been released to be used without long term testing, the massive increase in chemicals in our environment, water and food, not to say all the minute plastic particles that we are all ingesting has known and unknown effects.

In the UK there's also the problem of contraceptive pill residues in drinking water. There have been sufficient residues in rivers to make trout hermaphrodite. Must be having an effect on girls, too.

Opps forgot quote, a Dr says it has decreased from 16 to as low as 9 since the 1990s.

“Dr Parminder Singh, Endocrinologist, Ludhiana, told Mid-Day, "In the 1990s, menarche occurred among girls at age 16. This age has come down drastically, and nowadays anxious parents come to us when their daughters show signs of premature puberty at age 9 or 10. Cases of male children being diagnosed with gynaecomastia (breast enlargement) are on the rise."

In at least one part of Indian in the 1990s the average age of first menarch was 16.
sg.theasianparent.com/indian-kids-hitting-puberty-early

I read some years ago that once BMI/body fat reaches a certain level, periods start.
An article in the Times last week said that 28% of British adults are classified as obese. Alarming.

I did mention “pre industrial revolution” the industrial revolution came later in different places and also the diversity of more trade and more food sources. It’s still very recent historically.

It is disturbing that James Tanner photographed very vulnerable, orphaned children - with I assume no parents to protect and supervise (or refuse) - naked every 3 months to measure the development of puberty. As an orphan myself I find that extremely disturbing.

I was 14 and one of the last in my class. It was around 2007 my DD who's 9 has just started developing breast buds.

I was 16 but one if the last. I remember it being around 14 for most at school.

I've heard how we used to start our periods much later which is true, but longer ago than people think. Even the esteemed Elaine Miller said that the drop in the average age to around 12 is recent but I see no evidence for this.

I'm late 60s, started periods at 12 as did most of my class mates. Anecdotal, I know, but I do believe this 'periods started at 17' was in the Victorian era or before.

Yes I haven’t read the above article but since diets improved puberty has decreased from an average age of 17 to 12. 17 is pre industrial revolution in most places. It decreased drastically through the 20th century in many societies. I believe there are records from some Scandinavian countries that show it very clearly.

Very long article but i definitely think puberty is happening earlier for many. The link between high BMI and early puberty is interesting, I wondered if there was a link.