Scientists are proving that intestinal bacteria can help health — but for what conditions? Should you take probiotic supplements or eat foods with beneficial bugs? What does the science say — and not say?

Last week, Pres. Obama revoked the limits on studies of cells that can become any body cell. What was lost in eight years of limits on embryonic stem cells? What’s ahead?

A single neuron in the brain may deliver enough information to control a muscle. These results could eventually help bypass the spinal cord, allowing paralyzed people to control their own muscles.

Activity is not just for the heart: For older people, it spells longevity, mobility, independence. Exercise fights diabetes and MS; even extends the lifespan. Time to get moving?

Brain electrodes allow monkeys to move robot arm and feed themselves. Experiment proves it’s possible to bypass spinal cord to create simple motion.

New electronics, new sensors and new electrodes promise new hope for people with grave nerve disabilities. Replacements for both sensory and motor nerves have long ago left the drawing board.

New device translates brain signals into action, bypassing a destroyed spinal cord. Could this type of gadget help overcome paralysis?

What is EPO? What are steroids? Do steroids cause aggression? Are steroidal athletes bad role models? Are we over-reacting to steroid use?

Developmental biology meets dentistry as scientists grow human teeth in test tubes. All the latest on test-tube teeth. Sounds better than the iron teeth that the Romans used…

Hibernation gives clues about tissue preservation, organ transplants, stroke, Parkinson’s disease, brain behavior, and mating behavior. As the sun goes away, we look into the long snooze.