Americans will soon be able to test themselves for the virus that causes AIDS, now that the Food and Drug Administration has approved the first rapid, over-the-counter HIV test.
Even for infants born full-term, a little more time in the womb may matter. The extra time results in more brain development, and a study suggests perhaps better scores on academic tests.
They live on your skin, up your nose, in your gut — enough bacteria, fungi and other microbes that collected together could weigh, amazingly, a few pounds.