Biologists found new evidence why mice, people and other vertebrate animals carry thousands of varieties of genes to make immune-system proteins named MHCs – even though some of those genes make us sick.

Around 250 million years ago, most life on Earth was wiped out in an extinction known as the "Great Dying." Geologists have learned that the end came slowly from thousands of centuries of volcanic activity.

A new study finds a potential link between daily consumption of diet soft drinks and the risk of vascular events.

How will you feel if you fail that test? Awful, really awful, you say. Then you fail the test and, yes, you feel bad -- but not as bad as you thought you would. This pattern holds for most people, research shows. The takeaway message: People are lousy at predicting ...

Researchers have discovered new links between leukemia cells and cells involved in bone formation, offering a fresh perspective on how the blood cancer progresses and raising the possibility that therapies for bone disorders could help in the treatment of leukemia.

Generally speaking, a distinction has been made so far between “good” HDL cholesterol and “bad” LDL cholesterol. LDL contributes to cardiovascular diseases such as myocardial infarction and stroke, while the “good” HDL protects against them. Now, however, experts have discovered that the anti-inflammatory effect of HDL was not detected in ...

Your personality does more than seal social circles, it also can affect your health.

Here's a no-nonsense look at medical discoveries making headlines.

63 percent of Americans believe global warming is occurring.

Why do so many postmenopausal women who are treated for estrogen-sensitive breast cancer quit using drugs that help prevent the disease from recurring? The first study to ask the women themselves reports 36 percent of women quit early because of the medications' side effects, which are more severe and widespread ...

Dreaming may help to make bad memories feel less painful.

As young as 8 months, babies prefer characters who help helpful puppets and punish mean ones. The infants watched these puppet shows and then chose their favorite puppets of the bunch.