Puberty

                                               
Girls enter puberty about one year before boys. Girls usually begin to show the first changes a tender, nickel-sized lump under one or both nipples (breast buds) and then pubic hair – between the ages of 8 and 13. These changes precede a growth spurt, which is followed eventually by menstruation. Most girls get their first period 18 months to three years after the appearance of breast buds.

Some girls begin to show signs of puberty before age 8, and this condition is known as precocious puberty. If your daughter's breasts are developing or you notice pubic hair at age 7 or younger, let her doctor know. In most cases it doesn't signal a serious problem, but she may need testing to determine the cause and possibly receive treatment.

In boys, puberty usually begins between the ages of 9 and 14. The first sign is usually enlargement of the testicles followed by thinning and darkening of the skin on the scrotum. The scrotal skin also becomes dotted with tiny bumps, which are hair follicles. Pubic hairs begin to grow at the base of the penis, and the penis lengthens then widens. Boys go through a growth spurt as they progress through puberty, with most of the growth happening during late puberty.

Though it's less common, boys can also experience precocious puberty, which is defined in males as the onset of puberty before age 9.

Researchers continue to study the developmental differences between boys and girls and what causes them, but it's important to remember that biology alone doesn't determine the kind of son or daughter you'll have. Exposing your child to a wide range of activities and experiences is the best way to support a well-rounded, active child.