Reviewing the clinical landscape requires distinguishing between normal variations and pathology:
Pubertal development represents one of the most profound biological transitions in the human lifespan. It is a multifaceted process involving the maturation of the hypothalamic-pituitary-gonadal (HPG) axis, the development of secondary sexual characteristics, and radical neurobiological remodeling. This review examines the mechanisms triggering puberty, the interplay between hormones and brain development, the trend toward earlier onset (secular trend), and the psychosocial implications of this transition. pubertal development
These are the "messengers." They travel through the bloodstream to the gonads—the ovaries in girls and the testes in boys. In response, the gonads produce the sex steroids that drive visible changes: the development of secondary sexual characteristics