Human dignity

In the process of stem cell research, stem cells must be extracted from the blastocyst, so the human embryo is destroyed. Opponents of stem cell research claim that the destruction of human embryos is morally equivalent to the killing of a human being.

The morality of destroying human embryos for the benefit of others is the main argument in both  secular  and  religious  bioethics.  Opinions  regarding  the  ontological  status  of  preimplantation  embryos  vary  widely.  Some  hold  the  "conceptionalist"  view,  according  to which the embryo is a "person", considering its potential to develop into a person. Others believe that the embryo (and even the fetus) is a "non-person", and that it ought not to be attributed much, if any, moral status (DeWert & Mummery, 2003).

There is another viewpoint of the "relative value" of human embryos, more than cells but

less than persons (Hinman, 2009). This view states that embryos deserve respect but not to the same extent as a fully developed person. According to this moral argument, the moral status of a human embryo gradually increases through its development in the uterus, and at the  point  of  birth  it  is  entitled  to  enjoy  full  rights  of  human  beings  (United  Nations Educational, Scientific and Cultural Organization, 2004).

Another moral argument states that the status of embryos differs across milestones in the

process of embryonic development (United Nations Educational, Scientific and  Cultural Organization, 2004). In this argument, the question is at what point after fertilization of egg by sperm the cell mass becomes a human

being. This  seems an ethical impasse which science may not be able to resolve. For ethical  decision making on stem cell research, we should  determine  when  a  new  human  entity  comes  into  existence.  According  to  the scientific facts, there are significant points for delineation of human embryos, including: the moment of fertilization, the point of implantation in the uterus, the initial appearance of the primitive streak (19 days), the beginning of heartbeat (23 days), the development of brain waves (48 days), the point at which essential internal and external structures are complete (56 days), the point at which the fetus begins to move (12-13 weeks) (Hinman, 2009), and the point when the foetus would be viable outside the uterus (Balint, 2001).

As mentioned above, during the third week of human embryo development, the primitive

streak develops and three germ layers appear. Before this stage, embryos can  split and produce two or more embryos; however, after development of the  primitive streak, the embryo is a unique entity. In view of this fact, many believe that ontological individuality starts at this point, hence the embryo can be used for research prior to this stage; up to 14 days of development (DeWert & Mummery, 2003).

Religious schools also make various points which will be discussed later. There is no doubt

that an embryo is a living being whether or not it merits human rights. However, an entity would have the full rights and privileges of human beings when personhood begins.

There are different views on preimplantation embryos. Some bioethicists  suggested "the

trajectory argument" to defend the human rights of a human embryo before  implantation (Hinman, 2009).  According to this argument, since an early embryo has the potential to be a human being in the future, it deserves protection.  However, others claim that an entity before implantation is no more than a seed. There is also another viewpoint, according to which human embryos, even  if they are not persons, deserve respect (Hinman, 2009). As Hinman (2009, slide 20) concludes: "We can see some advocates of both sides of the hESCdebate as accepting the general principle of respect for innocent human life; their disagreement may not be over the principle, but over the way in which the principle is to be applied in particular cases."

The fear of "instrumentalization" of human embryos is a barrier to create embryos (DeWert

& Mummery, 2003). However, despite opposition to creation of embryos for research, there are arguments in support of the use of spare embryos in the process of IVF as sources of embryonic stem cells because such embryos would be destroyed anyway. Several hundred thousands of unwanted embryos are  discarded annually in IVF clinics. The use of such embryos before the appearance of the primitive streak is supported by many ethicists. However, as stem cells that are derived from surplus embryos may cause immune rejection when transplanted to a patient, some researchers emphasize the production of genetically identical stem cells by the use of cloning or other  techniques in order to avoid immune rejection   in   transplantation   (United    Nations   Educational,   Scientific   and   Cultural Organization, 2004).

The research carried out in Canada (Zarzeczny & Caulfield, 2009) shows that even though

issues related to the moral status of embryos continue to be a main issue in the literature on stem cell research, discourses associated with the moral status of embryos may not receive the  same  attention  in  social  and  other  realms.  For  instance,  while  the  moral  status  of embryos has a central role in legal discourse, it plays a relatively minor role in print media (Zarzeczny & Caulfield, 2009).