Stem cells are cells that are unspecialized because they aren't assigned to any body part, they divide and change into different types of cells. There are two types of stem cells: embryonic stem cells and adult stem cells. The embryonic stem cells are gotten from the embryo before it turns into a baby. The adult stem cells are gotten from donors bone marrow and blood. Embryonic stem cells can divide into all kinds of cells. Adult stem cells can't divide into all of the cells. Embryonic stem cell research causes controversy.
People say embryonic stem cell research is bad because scientists destroy the embryo and get the cells that are inside. People say that scientists are killing life when they do that because life is formed when the sperm fertilizes the egg. People say that we can research adult stem cells which doesn't kill life. They say that instead of killing life scientists should focus on gathering adult stem cells.
Other people argue that scientists are not killing life because "this cluster of cells" is not the same of a human person. They argue that life is formed after with the first heartbeat. They say that if they continue researching embryonic stem cells we can cure paralyzed people. Also, they argue that adult stem cells are harder to get than embryonic stem cells and they don't as well as embryonic stem cells. If they use induced pluripotent stem cells it will take longer to find cures for diseases.
It all comes down to where life begins. I say embryonic stem cell research should be done because scientists are not killing babies, they are using cells that were going to be destroyed anyway. Also, if we continue to study embryonic stem cells we could cure diseases which we thought were uncurable.