There are some 60 established stem cell lines that are approved for use in research (NIH, 2008). In making a case for expanding the now available stem cell lines obtained from embryonic tissue, Elfstrom argues (2001) that one should consider several reasons in making a decision in favor of this kind of research. First, one must consider the benefits that can be gained with regard to identifying the causes of many diseases and birth defects. Second, when causes are identified, treatments are likely to be forthcoming. This would certainly improve the quality of human life for many people. For example, it would be very important if somatic cell nuclear transfer (SCNT) was instrumental in helping to develop treatment to delay or eliminate the symptoms of Alzheimer's' Disease.
Secondly, Elfstrom (2001) makes the case that if SCNT is to be allowed, it is likely that the existing limited number of approved stem cell lines taken from embryonic tissue will soon be not enough to allow for complex research activities. It will be necessary to acquire more stem cell lines, and the way that he thinks is most appropriate is to make use of the "unwanted" embryos that are being held in freezers in fertility clinics that are not going to be used to create new life. He suggests that the current practice of simply throwing away such tissues is wasteful and that it is somehow disrespectful. Since it has become accepted practice to harvest organs from