Everyone is aware of the importance of umbilical cord blood cells  , and especially the importance that they could have in the future in regenerative and reparatory medicine. Cells from cord blood use in regenerative medicine is very useful but, one problem at present it that often only small numbers of these cells are collected. An article has now been published (Science 345; 1509-1512,2014) describing the development of a method to expand them (to increase their numbers). This could without doubt be a very useful alternative for bone marrow transplantation.