The development of secondary sexual characteristics varies in both boys and girls. The objective of this study is to identify the ages when adolescents enter their sexual maturity stages 2 through 5.

This study was based on annual pubertal assessments and included a total of 859 adolescents (aged 9½ to15½ years). Of 859 participants, 427 (49.7%) were boys, and 432 (50.3%) were girls. The primary outcome of the study was the change in the 5 stages of breast, genital, and pubic hair development.

The findings suggested that girls reached their breast maturity stages 2 and 3 earlier than their pubic hair stages. In girls, breast development started earlier than public hair development. However, girls completed breast development and pubic hair development at the same age. Boys, on the other hand, entered the 2, 3, 4, and 5 stages of genital development before their comparable pubic hair stage. In boys, genital development occurred before pubic hair development, but pubic hair development was completed in less time, as compared with genital development.

The research concluded that in both boys and girls, pubic hair development starts later than genital or breast development but finishes earlier or approximately at the same time.

Ref: https://jamanetwork.com/journals/jamapediatrics/fullarticle/382753?resultClick=1