What is the Tanner stage?
The Tanner stage (Tanner scale) is a clinical scale, accepted as standard worldwide, that defines the progress of puberty in five stages by looking at secondary sex characteristics. Stage I represents the pre-pubertal (childlike) period, and Stage V represents adult maturity. The intermediate stages show the gradual progress of development.
The scale looks at different markers by sex: breast development and pubic hair in girls; testicular volume, genital development and pubic hair in boys. These markers progress in a particular order alongside the growth spurt and other pubertal events.
Why is it used?
The Tanner stage objectively describes where a child is in puberty. This information is used to predict the timing of the growth spurt (PHV), to relate height prediction to maturation, and to assess whether the timing of puberty is within normal limits. For example, in girls the growth spurt usually occurs in the early-to-middle stages, while in boys it occurs at later stages.
It is also helpful as a maturation indicator in sport and training planning; but it gives the most meaningful information not on its own, but interpreted together with bone age and growth velocity.
Who should assess it and how?
Tanner staging requires a medical examination and is appropriately carried out by a doctor (a paediatrician or paediatric endocrinologist). It is neither necessary nor recommended for families to “stage” their own children; for privacy and accuracy, this assessment belongs in the clinical setting.
When a tool such as the platform asks for the Tanner stage, this is only optional context information and is entered if it has been determined by a doctor. It is not mandatory; even when it is not entered, height and maturation estimates can be made using other indicators.
The order and timing of the stages
Pubertal events do not progress randomly but in a particular order. In girls the process usually begins with breast budding; this is followed by pubic hair, the growth spurt and later the first period (menarche). An important point is that in girls the growth spurt occurs in the early-to-middle stages of puberty; the first period comes after the peak of the spurt, that is, after the major part of growth is complete. In boys the process begins with an increase in testicular volume, and the growth spurt occurs at a relatively later stage; this is why boys usually grow for longer.
Knowing this sequence allows families to answer the question “where are we, how much growth is left?” in a healthier way. When the Tanner stage is combined with bone age and growth velocity, a consistent picture emerges of where the child is in their growth journey. Stages progressing unexpectedly very early, very late or very fast, on the other hand, is a situation that requires a doctor’s assessment.