What age was the youngest boy to get armpit hair?

The onset of armpit hair in boys typically occurs during puberty, which can start as early as age 9. However, there have been rare cases of boys developing armpit hair at even younger ages, sometimes around 8 years old, due to precocious puberty. These instances are not common and can vary widely among individuals. Factors such as genetics and hormonal changes play a significant role in the timing of these developments.