New research conducted at the stem cell centre, DanStem, at the University of Copenhagen shows that insulin is a key determinant of embryonic stem cell potency in mammals. When large amounts of Insulin are around, stem cells retain their ability to make all the cell types in the body. However, too little insulin leads to embryonic stem cells being transformed into a new type of stem cell, one that can make tissues that support foetal development and helps make the different internal organs. As embryonic stem cells come from embryos around the time they implant into the mother, this study suggests that maternal insulin and diet maybe be important for the earliest stages of pregnancy. This study also points to new ways that stem cells can be made and differentiated to help treat degenerative diseases.