IvFindings and Recommendations•Human stem cell research holds enormous potential for contributing to ourunderstanding of fundamental human biology. Although it is not possible topredict the outcomes from basic research, such studies will offer the realpossibility for treatments and ultimately for cures for many diseases for whichadequate therapies do not exist.The benefits to individuals and to society gained by the introduction of new drugs ormedical technologies are difficult to estimate. The introductions of antibiotics andvaccines, for example, have dramatically increased life spans and improved the health ofpeople all over the world. Despite these and other advances in the prevention andtreatment of human diseases, devastating illnesses such as heart disease, diabetes, cancer,and diseases of the nervous system such as Alzheimer’s disease present continuingchallenges to the health and well-being of people everywhere. The science leading to thedevelopment of techniques for culturing human stem cells could lead to unprecedentedtreatments and even cures for these and other diseases.As with all research, our ability even tocontemplate the possibilities offered by stem cell-derived therapies is a result of many years of research. The science of stem cells dates tothe mid-1960s, and many papers have been published on the isolation and laboratorymanipulation of stem cells from animal models. While these models are imperfect, theyare accepted in the scientific community as good initial predictors of what occurs inhuman beings.There already exists evidence from animal studies that stem cells can be made todifferentiate into cells of choice, and that these cells will act properly in their transplantedenvironment. In human beings, transplants of hematopoietic stem cells (the cells whicheventually produce blood) following treatments for cancer, for example, have been donefor years now. Further, somewhat cruder experiments (e.g., the transplantation of fetaltissue into the brains of Parkinson’s patients) indicate that the expectation that stem celltherapies could provide robust treatments for many human diseases is a reasonable one.It is only through controlled scientific research that the true promise will be understood.