Difficult considerations must be taken into account in all areas of medical research and treatment and this is particularly so in the area of stem cell research and treatment, given that the European directive on funding for science is under consideration. There is little controversy regarding the use of adult stem cells, which are harvested from the adult who will be treated with them or another person, or the use of umbilical cord blood. However, for various reasons, a number of religions do not believe blood transfusions should be taken or given and they object to the use of stem cells from bone marrow or cord blood. Their ethical views must also be taken into account.