Stem cells, which hold the promise of new cell-based therapies to treat critical medical conditions, have to be effectively stored until it’s time to use them. The method is called cryopreservation: it freezes stem cells at temperatures below -150 o C, by immersing them in nitrogen vapour. But if the cells are to survive this process, they need to be frozen using a protective compound called a cryoprotectant, which is found to be toxic and can cause serious side-effects when administered. Research is on to find alternative, non-toxic compounds as protective agents of a technology which could rid the world of many diseases. In the past few years, it has become a norm to harvest the umbilical cord blood just after birth, as a guarantee of health for the child.