Embryonic stem cell | concern and controversy
The major concern with the possible transplantation of ESC into patients as therapies is their ability to form tumors including teratoma. Safety issues prompted the FDA to place a hold on the first ESC clinical trial, however no tumors were observed.
The main strategy to enhance the safety of ESC for potential clinical use is to differentiate the ESC into specific cell types (e.g. neurons, muscle, liver cells) that have reduced or eliminated ability to cause tumors. Following differentiation, the cells are subjected to sorting by
Due to the nature of embryonic stem cell research, there are a lot of controversial opinions on the topic. Since harvesting embryonic stem cells necessitates destroying the embryo from which those cells are obtained, the moral status of the embryo comes into question. Some people argue that the 5-day old mass of cells is too young to achieve personhood or that the embryo, if donated from an IVF clinic (which is where labs typically acquire embryos from), would otherwise go to medical waste anyway. Opponents of ESC research counter that any embryo has the potential to become a human, therefore destroying it is murder and the embryo must be protected under the same ethical view as a developed human being.