Biology and You

You and Your Cells

What is a stem cell, and why is “stem cell research” so controversial?

Stem cells are undifferentiated cells—meaning that they do not have a specific function—that are capable, under certain conditions, of producing cells that can become a specific type of tissue. Stem cells present in adult humans are found in bone marrow and other tissues (such as fat). However, most research interest is focused on stem cells present in fetal tissue, which, in a laboratory setting, can reproductively divide indefinitely and be stimulated into becoming a variety of different cell types. The potential benefits of stem cells have made the research of these cells an exciting research topic. In fact, stem cells could be used to grow new hearts that could be transplanted without fear of rejection or to renew the function of injured structures like the spinal cord. They could also be used as cell models for drug testing, thereby increasing the speed for finding cures. But the main controversy stems from the actual “harvesting” of the most useful stem cells—from fetal tissues from human embryos—especially the question of what point in cellular growth constitutes a “human.”


This is a web preview of the "The Handy Biology Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App