The problem with the embryonic stem cells are the many complications associated with them. Besides the ethical considerations, from a practical point of view, we are still a long way from being able to utilize these cells in a safe and consistent manner.

When using embryonic stem cells, you are inheriting any potential diseases that the baby may have. For instance, the baby may have a gene that increases susceptibility to cancer. In fact, the embryonic cells themselves may act as a tumor since there is no natural check on these cells. Furthermore, these cells are foreign materials to the body, and the body will react and attack these cells in an immune response. This can sometimes cause a serious medical condition called graft versus host disease. In that case, the patient may have to be placed on immunosuppressant drugslike an organ transplant patient. With our present technology, embryonic stem cells are not the answer. For those reasons, the FDA has put significant restrictions on the use of this type of cell in humans.

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Boston Stem Cell Center - Bone Marrow Stem Cells in ...