Adolescent sexuality is a stage of human development in which adolescents experience and explore sexual feelings. Interest in sexuality intensifies during the onset of puberty, and sexuality is often a vital aspect of teenagers' lives. Sexual interest may be expressed in a number of ways, such as flirting, kissing, masturbation, or having sex with a partner. Sexual interest among adolescents, as among adults, can vary greatly, and is influenced by cultural norms and mores, sex education, as well as comprehensive sexuality education provided, sexual orientation, and social controls such as age-of-consent laws. Sexual activity in general is associated with various risks and this is heightened by the unfamiliar excitement of sexual arousal, the attention connected to being sexually attractive, and the new level of physical intimacy and psychological vulnerability created by sexual encounters. The risks of sexual intercourse include unwanted pregnancy and contracting a sexually transmitted infection such as HIV/AIDS, which can be reduced with availability and use of a condom or adopting other safe sex practices. Contraceptives specifically reduce the chance of teenage pregnancy. The risks are higher for young adolescents because their brains are not neurally mature. Several brain regions in the frontal lobe of the cerebral cortex and in the hypothalamus that are deemed important for self-control, delayed gratification, risk analysis, and appreciation are not fully mature. The prefrontal cortex area of the human brain is not fully developed until the early 20s or about age 25. Partially, because of this, young adolescents are generally less equipped than adults to make sound decisions and anticipate consequences of sexual behavior, although brain imaging and behavioral correlation studies in teens have been criticized for not being causative. Development of sexuality Adolescent sexuality begins at puberty. The sexual maturation process produces sexual interest and stimulates thought processes. Subsequent sexual behavior starts with the secretion of hormones from the hypothalamus and anterior pituitary gland. These hormones target the sexual organs and begin their maturation. Increasing levels of androgen and estrogen have an effect on the thought processes of adolescents and have been described as being in the minds "of almost all adolescents a good deal of the time". Though most female adolescents begin their sexual maturation process in normal, predictable ways, there may be concerns by parents and clinicians if the following become evident: painful menstruation chronic pelvic pain partial vaginal outflow obstruction/imperforate hymen possible anatomical defects Views on sexual activity