TOKYO -- The stem cell technology developed by Japanese Nobel laureate Shinya Yamanaka is often described as a method of "turning back the clock" on ordinary human cells. This has raised hopes that, someday, scientists might be able to reverse the hands of time and rejuvenate old human bodies.
About a decade ago, Yamanaka discovered a groundbreaking technique for reprogramming adult cells into induced pluripotent stem, or iPS, cells. If you take a skin cell from a 70-year-old man, for instance, and add three or four genes to it, it will turn into something very similar to an embryonic stem cell. This means it can develop into any type of human cell.