I had a question about the precocious age range. My instructor said before 9.5 but many other books say 9 for boys and girls. How would they treat that? Doesn't this vary by ethnicity? I am just trying to understand the sequences and tanner stage age ranges. For girls isn't it breast growth than pubic hair? There aren't any genital stages for girls, right?
According to Mayo Clinic: "Precocious puberty is when a child's body begins changing into that of an adult (puberty) too soon. When puberty begins before age 8 in girls and before age 9 in boys, it is considered precocious puberty." ["Precocious puberty"]
The hormones rise in the blood approximately the same time in both boys and girls, but on average, boys don't show external signs of changes until a year later than girls. Girls also develop quicker than boys, spending an average of 1.5 years per stage while boys spend about 2 years per stage.
There a number of rare causes for precocious puberty in children, such as a tumor, but for the vast majority the cause isn't known. All we know is that the sequence starts too soon. Children of African descent tend to have precocious puberty more often than other children and girls tend to have it more often than boys.
The main concern with precocious puberty is that the child's final height will typically be less because the starting height for developing is less.
If there is no obvious cause, such as a tumor, treatment is to use hormones to slow down the rate of development so that the body can gain some height before growth ends.
There are several areas of the body that develop in a sequence, but the sequence of the areas may vary. Thus, pubic hair or breast development goes is a particular order, but whether pubic hair starts first or breasts start first will vary individually. There is genital development but because they are not as easily seen as in boys, it isn't often used to mark the Tanner Stages.