What is typically an early indicator of development stage in young girls according to Tanner stages?

The development of breast buds is indeed recognized as an early indicator of the development stage in young girls according to Tanner stages. Tanner stages, also known as the Tanner scale, classify physical development based on external primary and secondary sexual characteristics. In females, the first stage of development, which typically occurs during early adolescence, involves the burgeoning of breast buds, known as thelarche. This is one of the earliest signs of puberty and signifies that the body is beginning to undergo changes associated with sexual maturity.

Breast development usually precedes other physical changes such as the growth of pubic hair or the onset of the menstrual cycle. While an increase in height is a common change during puberty, it can occur after or alongside the development of breast buds, but it is not a primary indicator of the early stage of development as defined in Tanner's assessments. Thus, the presence of breast buds serves as the most reliable early marker for the onset of puberty in young girls.