Appendix 1. Tanner Stages of Sexual Maturation

Tanner Staging Ranges from 1 (Prepubertal) to 5 (Adult Development)[1]

Stages	Girls—Breast Development	Girls and Boys—Pubic hair	Boys—External Genitalia Development
Tanner Stage 1	Prepubertal Only the papilla is elevated above the level of the chest wall	Prepubertal (velus hair similar to abdominal hair)	Prepubertal (velus hair similar to abdominal hair) Testes, scrotal sac, and penis have size similar to early childhood
Tanner Stage 2	Breast budding, elevation of breasts as small mounds, enlargement and widening of areolae. May be tender and not symmetrical bilaterally	Sparse growth of long, slightly pigmented, downy, straight or curled hair on labia majora or at the base of the penis	Enlargement of scrotum and testes; scrotum skin will thin and may be redden
Tanner Stage 3	Breast enlarges, elevating beyond the areolae	Pubic hair becomes curly, coarser, extends outward over junction of pubes	Penis lengthening, testicles continue to grow
Tanner Stage 4	Breast enlarges and areolae and papilla form secondary mounds	Hair adult in type, but covers smaller area, no spread to the medial surface of thighs	Penis and testicles grow, scrotum darker in color
Tanner Stage 5	Breast achieves adult contour	Hair adult in type and quantity extends onto medial thigh	Adult genitalia

Changes in Girls and Boys at Various Stages of Sexual Maturation

(Original illustration from Johnson, Moore, & Jefferies. (1978). Permission to use obtained from Abbott Laboratories, Nutrition Research and Development.)

[1] The scale was developed with reference to a single ethnic group and a relatively small sample of only 200 children, so using this as a measure may not apply to all ethnic groups (Blackemore, Burnet, & Dahl, 2010). Different ethnic groups may have variations in breast development, pubic hair growth, distribution, or growth patterns. Care should be taken to assess children for pubertal development based on a knowledge of local ethnic variations and common characteristics.