Also, Doppler can detect abnormal blood flow within the heart, which can indicate a problem with one or more of the heart's four valves. Color Doppler. Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow.
Earlier Puberty: Age 9 or 10 for Average U.S. Boy. Oct. 20, 2012 -- American boys are starting puberty up to two years earlier than decades ago, new data show. Boys are entering puberty at an average age of 10 among whites and Hispanics, and at an average age of 9 among African-Americans. About a third of boys start to mature sexually up to two years earlier than average.
1 Your beard, which is the hair on your cheeks, chin, and neck, may also start to come in.  The pits: As puberty starts, you'll begin growing hair underneath your arms. It will probably be light and soft at first, but will get thicker as you get older.