Teenage is a transitional stage of physical and mental development, generally occurring between puberty and legal adulthood. Puberty marks the beginning of adolescence and is the period of time when males and females become physically able to reproduce A teenager is a person between the ages of 13 and 19.The end of adolescence and the beginning of adulthood varies by country and by function, and furthermore even within a single nation-state or culture there can be different ages at which an individual is considered to be (chronologically and legally) mature enough to be entrusted by society with certain tasks.
Promoting healthy behaviour among this age group aims to encourage the development of healthy adult lifestyles. Teenagers are acknowledged to be at high risk of health-damaging behaviours including smoking, teenage pregnancy, and drug and alcohol use
Adolescence is typically a time for experimenting with risky behaviours, despite good parenting practices and role modeling.