Kids who are starting to go through puberty may notice new hair on their legs or in their armpits, especially if it's thick or dark in color. Some may want to shave it and others may not be bothered ...

How Does Air Enter the Respiratory System? Air enters the respiratory system through the nose or the mouth. If it goes in the nostrils (also called nares), the air is warmed and humidified. Tiny hairs ...

Herd immunity is the idea that when many people are immune to (protected from) a contagious infection, it's harder for that infection to spread in a community. Antibody shots against specific germs ...

What Is a Breath-Holding Spell? A breath holding spell is when a child holds their breath, usually after being angry, frustrated, startled, or in pain. Sometimes the breath holding leads to the child ...

What Causes Osgood-Schlatter Disease? Osgood-Schlatter disease happens during the growth spurt of puberty. During a child's growth spurt, the bones, muscles, and tendons grow at different rates. In ...

It’s normal for people to masturbate (touch or rub their own genitals because they like the way it feels). Some people do it to relieve stress or tension. It’s nothing to be ashamed of or embarrassed ...

Flat feet are feet that do not have an arch. The middle of the foot touches the ground. Feet with no arches is the main sign of flat feet. Sometimes, flat feet can cause foot, ankle, or knee pain.

We see and hear about hearts everywhere. A long time ago, people even thought that their emotions came from their hearts, maybe because the heart beats faster when a person is scared or excited. Now ...

Just about every guy wonders how he measures up "down-there." Here's the lowdown for any guy who's ever worried about whether his penis is a normal size. There is a wide range of normal penis sizes.

How much do you know about your lungs? Find out by taking this quiz!

When people masturbate, they touch or rub their own genitals because they like the way it feels. This won’t stunt their growth (keep them from getting taller) or cause any health problems. You might ...

How Can I Help My Child Manage Anxiety? Feeling nervous, worried, or uneasy at times is a normal part of growing up. Helping your child feel more in control and able to cope with stress can help ...