What can a specialized cell do for all of mankind? Scientists are continually finding answers to this question. Stem cells have acquired much attention for their potential to become a wide variety of specialized cells. These replacement cells can be used to treat brain and blood disease, therapy for cell deficiency, general scientific discovery, and perhaps the most important application, regenerate organ and body tissue. With all these life-changing uses stem cell research is exceedingly controversial for ethical reasons.
Debates that surround stem cells are concerns with the methods of extracting embryonic stem cells for research. Stem cells come from two main sources: adult tissue, and embryos formed during embryological development. Embryonic stem cells are derived from a four-day-old human embryo during the blastocyst phase of development. The fertilized eggs are not given the chance to become a fully developed human.
Some say that life begins at conception, when the egg is fertilized arguing that the embryo deserves the same status as any other full grown human. By removing the blastocyst to extract the stem cells is argued comparable to murder. The other side contends there are different points in gestational development (development of certain organs after certain time periods) that mark the beginning of life.
Since science doesn't differentiate whether research is ethical or not, it makes it difficult to answer the question "When does life begin?" Similar to debates about abortion this is the core question of this debate. Are the advancements in medicine made possible by stem cells worth the potential lives that are being killed to replenish broken cells?
Going more in-depth in the political and scientific debate of stem cells, this article from TIME advocates both ends of the spectrum and describes possible alternatives.