Thelarche is defined as the onset of what?

Thelarche is defined as the onset of what?

• A. Onset of pubic hair growth
• B. Appearance of sperm
• C. Onset of breast development
• D. Onset of gonadal function

Answer: (C)

Thelarche is the first visible sign of puberty in girls—the onset of breast development driven by estrogen. It marks the initial breast tissue changes (beginnings of breast buds) that occur as puberty begins. This is distinct from pubarche, the onset of pubic hair growth driven by androgens; spermarche, the appearance of sperm in males; and gonadarche, the broader activation of the gonads that drives overall pubertal hormonal changes. So breast development best defines thelarche.

Thelarche is the first visible sign of puberty in girls—the onset of breast development driven by estrogen. It marks the initial breast tissue changes (beginnings of breast buds) that occur as puberty begins. This is distinct from pubarche, the onset of pubic hair growth driven by androgens; spermarche, the appearance of sperm in males; and gonadarche, the broader activation of the gonads that drives overall pubertal hormonal changes. So breast development best defines thelarche.