You've probably seen artificial skin before, but never has it been quite so... accurate. Japanese researchers have grown skin tissue that not only includes hair follicles, but all the glands that come with it -- including oil and sweat glands. The trick was to take cells from mouse gums, turn them into stem cell-like forms that generate skin, and implant those into mice with immune system deficiencies (which lets the new skin grow unimpeded). The resulting skin was a little creepy -- just look at the wart-like growth above -- but it was healthy, behaved normally and made connections with natural tissue.