"Youth would be an even better time, if it came later in life." Charles Chaplin [1]
(translated by Christine Wilhelm) 

Adolescence is the time of sexuality maturity, also called puberty. Experts are still in disagreement regarding the exact time period since it varies according to biological, (physical), mental and psychological human development that generally occurs during the period from puberty to legal adulthood which hypothetically is between the age of eight and twenty. [2] [3]

At first, the pituitary gland stimulates the ovaries and testicles via neurotransmitters. Then, sex hormones are released, the ovaries predominantly dispense estrogens and progesterone as well as testosterone to a lesser extent. Factors like stress, lack of nutrients, trauma etc. can contribute to delayed puberty. [3] [4] [5]

A surge in hormone production causes physical changes like the appearance of pubic hair, the development of breast tissue, the onset of menstruation (menarche) and the change of vagina and uterus for possible inercourse and pregnancies. [3] [5] The physiology of the vagina also changes insofar as the initially neutral pH-value descends to acid conditions, that is, a pH-value of 4. This protects the vagina against germs and diseases. [6]

Due to the hormonal flooding the adolescent brain also experiences a process of resctructuring. Sexuality awakens in a turbulent way. According to Anna Freud, an Austrian-British psychoanalist and Sigmund Freud's daughter, the release of new libidinal energies leads to impulsive curiosity, egocentrism and aggression. [7] The „I" is stronger defined by dissociation which often finds expression in the rejection of educators. [3]

According to E.H. Erikson's psychosocial model, adolescence is characterized by search for identity. Between the age of 13 and 20, one not only questions the role of reference persons, but also raises questions about one's role in a peer group, the other sex, the role in one's job as well as the big question „Who am I?". A healthy personal identity can only be established if one can deliver a positive summary of past situations and has good self-confidence. In case of predominant negative experiences, teenagers suffer a confusion of identity and look for support in groups with clear structures. [8]