Designing effective ways to reduce both teen pregnancy and unsafe sex requires knowing how many girls are actually having sex and using contraception.

Prevention of allergies in children is a murky science. Some parents may add prebiotic supplements to baby formula in the hopes that the prebiotics could reduce allergy risk.

Dozens of studies have debunked the one study that falsely tried to link vaccines to autism. Yet some parents remain concerned about possible negative effects of children's vaccines.

One concern many parents have about getting their children immunized is the pain of multiple shots. Is it possible a spoonful of sugar really would help ease any pain from the needles?

Researchers already knew that milk allergy was common among American children. But until recently, they weren’t sure how it compared to other food allergies.

It's still not clear what kind of effects watching too much TV or playing video games can have on children. There are many different factors researchers have to consider.

Having difficulty conceiving a baby over a long period of time may indicate a condition called subfertility. Subfertility carries its own slight risks if parents eventually do have a baby.

The US has one of the highest teen pregnancy rates among developed nations. Understanding the risk factors for teen pregnancy might lead to effective prevention.

The effects of a mother's body on her developing child are still mysterious in many ways. For example, the possible effects of emotional stress on a baby aren't totally understood.

Extremely premature birth is linked to difficulties with thinking and motor skills. But researchers are still learning what it means even if children are born only a few weeks early.