Thelarche is the first pubertal sign in girls; what is its typical age range?

• A. 9-14
• B. 6-9
• C. 11-16
• D. 8-13

Answer: (D)

The main idea is that thelarche, or breast development, is the first sign of puberty in girls and is driven by estrogen. This initial puberty milestone typically appears in early to mid-childhood, commonly beginning around 8 to 13 years of age, with most girls showing breast budding around 9 to 11. This window reflects normal variation in timing due to genetics and other factors, so 8-13 captures the usual range.

Options that place onset earlier or later than this range are less representative of the typical timing. While some individuals may start slightly outside the window, 8-13 remains the standard reference for the age when thelarche commonly begins.