what factor is often related to the onset of puberty for females?
U.S. girls are entering puberty at a younger age than in the past. More than 10 percent of white 7-year-old girls have breast changes that signal the start of puberty, according to a study conducted in the mid-2000s. This is up from just 5 percent in the early 1990s.
You might think this doesn't mean a lot but, hormones cause the changes that are associated with puberty. 1  Timing of Puberty. 2  Genitalia & Pubic Hair. 3  Growing. Possible Breast Development.  Voice 1  Change. Body 2  Hair.  Acne.