Maturation is the process that leads to the achievement of adult maturity. Maturation is a part of development. Both relate to progressive increases in complexity, but maturation is restricted to those developmental changes that lead to the same end point in all individuals. For example, the percentage of adult stature achieved by a child is a measure of maturity: all reach 100% in adulthood. Levels of maturity that are intermediate between the absence of measurable indicators and the adult state indicate the extent to which a child, or a group of children, has proceeded toward the completion of maturation in a particular body system. Maturation occurs in all body systems, organs, and tissues. For example, ‘skeletal maturation’ refers to a set of radiographically visible changes that culminate in the achievement of adult skeletal status by the early 20s.

This broad subject has received considerable sustained attention from Fels scientists. For example, Roche (1974c180) published an introduction to a symposium on adolescent physiology in which variation in maturation was the dominant theme. Much of this variation is associated with differences in rates of maturation among individuals. Attention was also given to the hormonal control of adolescence and the factors that regulate the timing of menarche. Maturation has also been the subject of a review by Chumlea (in press13).