It makes sense that fetal stem cells would be more active than adult cells. After all, we’ve all seen kids with incredible healing powers and we’ve all observed our own healing prowess get less as we age. However, a recent study reversed this thought trend. In this study, they examined the protective effect of adult mesenchymal cells taken from bone marrow on a myocardial infarction (heart attack). Much to every one’s surprise, they found that while the adult stem cells were able to protect the heart muscle from damage, neonatal stem cells, when used for the same purpose, did not protect the heart muscle. The authors believed that the fetal stem cells likely did not have a gene switched on which usually helps stem cells protect other adult cells. Interesting finding, maybe these old dog adult stem cells can teach those young whippersnapper fetal stem cells a thing or two!