Male and Female Puberty: Hormonal Changes and Physical Development

Puberty: Hormonal Activation and Secondary Sexual Characteristics

Hypothalamic-Pituitary-Gonadal Axis Activation

GnRH pulse generator reactivates → LH/FSH → gonadal steroid production.

Male Puberty (Typical Onset 9-14 years)

Tanner Stage	Testicular Volume	Penis	Pubic Hair	Other
I (Prepubertal)	<1.5 mL	Childlike	None	—
II	1.6-6 mL	Slight enlargement	Sparse, long, straight	Scrotal thinning/reddening
III	6-12 mL	Lengthening	Darker, coarser, curling	Peak height velocity
IV	12-20 mL	Width > length	Adult-like, not medial thigh	Voice deepening, axillary hair
V (Adult)	≥20 mL	Adult size	Medial thigh spread	Facial hair, muscle mass, spermatogenesis

Female Puberty (Typical Onset 8-13 years)

Tanner Stage	Breasts	Pubic Hair	Menarche	Other
I	None	None	—	—
II	Budding	Sparse	—	Growth spurt begins
III	Elevated mound	Darker, coarser	—	Peak height velocity
IV	Areola mound	Adult-like, not medial thigh	—	Menarche typically late III/IV
V	Adult contour	Medial thigh spread	Regular cycles (1-2 yr)	Ovulation established

Key Hormones

• Testosterone (M): Virilization, anabolic, libido.
• Estradiol (F): Breast/uterine development, bone, fat distribution.
• Adrenarche: DHEAS → pubic/axillary hair, acne, odor (independent of gonadarche).

Variations Requiring Evaluation

• Precocious puberty: <8 yr (F), <9 yr (M).
• Delayed puberty: No breast/testicular enlargement by 13 (F), 14 (M); no menarche by 15.
• Disorders of sexual development (DSD).