Adolescents Adolescents 1. Puberty ends when an adolescent is sexually mature .
Girls are sexually mature when they start menstruating.
Boys are sexually mature when the testes produce sperm. Sexually mature people can reproduce . Sexually mature girls can have babies and become mothers. Sexually mature boys can impregnate females and become fathers. While adolescents are sexually mature when puberty ends, they are rarely, if ever, emotionally or socially mature as long as they are adolescents 4.