 Further issues emerge with the prospect of being able to produce large quantities of eggs from stem cells.  As the capacity to identify disease and non-disease related alleles through preimplantation genetic diagnosis (PGD) expands, the ability to create large numbers of embryos would substantially increase the chances of finding an embryo that possesses most or all of the traits one wishes to select. This would be beneficial in preventing the birth of children with genetic diseases.  But matters would become morally contentious if it were possible to select for non-disease characteristics, such as sexual orientation, height, superior intelligence, memory, and musical ability.  One common argument against using PGD in this way is that it could devalue the lives of those who do not exhibit the chosen characteristics.  Another concern is that employing PGD to select for non-disease traits would fail to acknowledge the “giftedness of life” by treating children as “objects of our design or products of our will or instruments of our ambition” rather accepting them as they are given to us (Sandel 2004, 56).  There is additionally a concern about advances in genetics heightening inequalities where certain traits confer social and economic advantages and only the well-off have the resources to access the technology (Buchanan 1995).  Of course, one can question whether the selection of non-disease traits would in fact lead to devaluing other characteristics, whether it would alter the nature of parental love, or whether it is distinct enough from currently permitted methods of gaining social and economic advantage to justify regulating the practice.  Nonetheless, the capacity to produce human stem cell-derived gametes would make these issues more pressing. 