Stage 5 – Adulthood

Typical Age Range

This stage starts when growth in height stops and lasts the rest of adult life. On average it starts around age 17 but can start as early as 15 or as late as 20.

Characteristics and Changes During Stage 5:

Even after stage five is reached, changes still take place for the several more years.


Growth in height stops. This is the primary marker for the start of stage 5.


The scrotum is at its adult size. The testes are longer than 1 3/4 inches (4.5 cm) long measured along the long axis or over 20 ml in volume.

Penis has full adult characteristics.


Pubic hair covers groin and the inner thighs.

Chest hair develops.

Full facial hair develops.


Muscles are easily developed.

Shoulders widen to give a typical male physique.

Chin widens, giving a squared off look.


The brain continues to develop reaching typical adult thought patterns by about age 24. During the early part of stage 5 males tend to be rash in their behavior, doing things without fully thinking about the consequences of their actions.