1,439. Exhibiting Signs Prematurely

Hilchos Ishus 2:18

As discussed, if a girl grows two pubic hairs before the age of 12, or a boy does so before the age of 13, it is considered as if they were hairs growing from a mole. Even if these hairs remain after the child has reached the age of majority, they are not considered a sign of maturity.

Hilchos Ishus 2:19

The above halacha only applies if the child was examined and the hair was ruled to be the equivalent of hair growing from a mole. If no examination was made until after the child reached the age of majority, at which time an examination was made and two hairs were found, then they are considered a valid sign of maturity. We are not concerned that the hair might have grown before the child reached the age of majority and should be considered as if growing from a mole.