When do girls and boys start puberty?

Puberty: Puberty for girls typically starts at age 10 and continues for about 3 years after their periods start (around 16-17) . Boys may begin puberty as early as 12 and continues for 3-5 years. the majority of growth, sexual characteristics and body hair will occur during this time.

Lots of variation : Agree with Dr Kratzberg, but there is a wide variety among people, so usually not to worry if a young girl starts her period @ 9 years old or as late as 16, or similar variation with boys. It can be stressful to young people though, when they compare themselves with peers! Parents should encourage their teens & preteens that each is unique & valuable.