STEM cells are something that can affect a vast variety of medicine. While largely unrelated to fields in Biology like Ecology or Animal Behavior, you may want to look into molecular biology, genetics, or contact researchers at your local university. As far as progress, originally STEM cells had to be gathered from human and mouse embryos. This caused a lot of controversy over the ethics how these could be gathered. Now we are able to gather them from amniotic fluid and from umbilical cords, which is both cheaper, and less problematic. While STEM cells are not largely sued at the moment, they are currently being researched in a vast variety of diseases from autoimmune to degenerative diseases. They truly are a new and growing field that will pave the way for medical advancements.