Blue light may trigger hormonal changes that could lead to the early onset of puberty.
Girls are entering puberty a year earlier than their mothers' generation, Science
Child development - Wikipedia
Early puberty: Growing older sooner
New evidence suggests early puberty can be triggered by pandemic stress
Early Onset of Puberty in Girls on the Rise
Early Pubertal Timing and Testosterone Associated With Higher Levels of Adolescent Depression in Girls - Journal of the American Academy of Child & Adolescent Psychiatry
Eating disorders in teens more than doubled during pandemic
What to Know About Puberty Starting Earlier
When Is Puberty too Early?