The application of growth charts to adolescents requires an understanding of normal growth and development during puberty. More than 40 years ago, James Tanner and associates began describing the normal physical changes that occur during puberty. Tanner has noted that "the only thing that is constant about puberty is change."
Besides the obvious differences of the genitalia and secondary sex characteristics between males and females, there are also differences between individuals who develop early compared to those who develop later in their teenage years. This context of change must be appreciated when using growth charts with adolescents.
Tanner and colleagues
serially measured and photographed a large number of normal British males
and females to determine the physical changes that adolescents experience
as they grow from boys to men and from girls to women.
The two physical elements of sexual maturity rating for girls are: