The global population today is young. Adolescents between 10 to 24 years of age make up over 1.8 billion of the global population. This is the highest number in history. 9 out of 10 adolescents live in developing countries, where challenges in achieving their potential and securing healthy wellbeing persist (UNFPA, 2014). Adolescence is critical stage of transition from childhood to adulthood. Considered to begin with puberty, the mean age for girls is thought to be between 12 and 13 years of age – where they experience the first menstruation, a distinct marker. For boys, there is no distinct marker, but signs of sexual maturation are exhibited between 13 and 14 years of age (UNDESA, 2012).
Globally, Adolescents are almost equally distributed by age groups and sex between age groups of 10 – 14 and 15–19. This trend is expected to continue for decades to come. The largest increase, particularly of adolescent girls, in the coming years will be in Africa, rising markedly with 1 in 4 adolescent girls living in Sub-Saharan Africa. (UNFPA, 2013).