Video games prop open a door in kids' brains, creating an opening through which knowledge can march with almost no resistance. Game-playing children absorb enormous amounts of information and develop outlandishly high skill levels. Trouble is, virtually none of what they learn has any value beyond the joystick and glowing screen.

But medical researchers are also exploiting the magical power of video games to convey useful information. Recent findings provide compelling evidence that the right games can train kids with diabetes and asthma to keep their conditions under control.