A helpful look at what to expect with your newborn—from your baby's growth and reflexes to crying and emotional development.

Read on for helpful suggestions for activities and toys for your baby, according to their age.

If you know anything about your baby's sleeping pattern, it's probably that it doesn't coincide with yours. But learning more about your baby's nighttime and daytime sleep needs can help you recognize what's normal, and what's not.

Detailed information on what teen boys can expect during a physical exam.

Bipolar disorder is a type of depression. A teen with bipolar disorder often has extreme mood swings. These mood swings go beyond the day's normal ups and downs.

Cognitive development means the growth of a child's ability to think and reason. This growth happens differently from ages 6 to 12, and ages 12 to 18.

Bulimia nervosa is an eating disorder. A child with bulimia overeats or binges uncontrollably. This overeating may be followed by self-induced throwing up (purging).

Circumcision is a surgery to remove the skin covering the end of the penis. This is called the foreskin. This surgery is most often done 1 or 2 days after a baby's birth. Read on to learn more about this procedure.

Birth defects may be caused by inherited (genetic) problems or by environmental things, such as exposure to certain toxic substances during pregnancy. Some birth defects can be linked to a direct cause. Other reasons are not as clear.

Detailed information on cystic fibrosis and its effect on the respiratory system.