Typical Age Range
This stage starts at birth and continues until the first signs of puberty are reached. On average, it ends around age 11, but can end as early as 9 or as late as 15.
Characteristics and Changes During Stage 1:
Growth
This stage lasts from birth to puberty. The typical growth rate is about two inches (5 to 6 cm) per year.
Genitals
Testes are less than 1 inch (2.5 cm) in length, measured along the long axis, or 1.5 ml in volume.
Hair
No body hair or very fine hair that is not easily noticed.
Body
The areola is barely noticeable and follows the skin contour of the chest.