  When spare embryos exist after fertility treatment, the individuals for whom the embryos were created typically have the option of storing for them for future reproductive use, donating them to other infertile couples, donating them to research, or discarding them. Some argue that as long as the decision to donate embryos for research is made after the decision to discard them, it is morally permissible to use them in HESC research even if we assume that they have the moral status of persons. The claim takes two different forms. One is that it is morally permissible to kill an individual who is about to be killed by someone else where killing that individual will help others (Curzer, H. 2004). The other is that researchers who derive HESCs from embryos that were slated for destruction do not cause their death. Instead, the decision to discard the embryos causes their death; research just causes the manner of their death (Green  2002).