"What it does: Collects, tests, and stores umbilical-cord stem cells. If the babies — and, in some cases, their relatives — are affected by blood cancers or genetic diseases down the road, the cells can be used to rebuild their immune systems. Why it's growing: The political debate over stem-cell research has familiarized people with the concept. ViaCell collects and stores cells only from umbilical cords, avoiding controversial embryonic cells. Obstetricians tell their patients about ViaCell and receive a procedural fee each time parents have a baby's cells collected and stored. Postscript: ViaCell went public in January; it trades on the Nasdaq exchange."