UPDATE: the so-called “personhood amendment” has been voted down.

Mississippi residents will vote today on a constitutional amendment to change the legal definition of personhood to include fertilized human eggs. The amendment would outlaw all abortions (including those resulting from rape or incest), many forms of birth control (including IUDs and morning-after pills), and embryonic research.

As previously discussed, the amendment is absurd both philosophically and legally. But as detailed by bioethicist Art Caplan, considering fertilized eggs as “persons” also flies in the face of what we know about medicine and science: 

This is what we know: During the period of embryonic development that begins with fertilization and ends with successful implantation, about 50 percent of human conceptions fail to survive. The main reason for this high failure rate is the inability of huge numbers of fertilized eggs to implant.  

What science has found is that around half of all conceptions don’t make it to implantation. Calling a fertilized egg a person flies in the face of this cruel biological reality. Half of all fertilized eggs cannot even become an embryo, much less a person.

Indeed, given the grim odds that face fertilized eggs, no one in science or medicine refers to a fertilized egg as an embryo unless it manages to implant. By talking about embryos and fertilized eggs as equivalent, supporters of Initiative 26 are not even using the correct scientific definition of an embryo.

If the rest of the story of human reproduction — as medicine and science know the facts to be — is brought to bear, things only get worse for Initiative 26.

Sadly, all too many couples know about the high rate of spontaneous abortion and stillbirth that haunts embryonic and fetal development. Roughly, one in six embryos will spontaneously abort or produce fetuses that do not develop properly and die in utero. 

There are a huge number of embryos that are not properly genetically programmed for life. Nearly all of these completely lack the biological ability to develop into anything resembling a viable baby.  Legislation — like that about to be voted on in Mississippi — that declares fertilized eggs to be persons from the moment of conception simply ignores that the failure rate of human embryos is very high.  A considerable number of embryos and fetuses never have any chance of producing a baby. 

Medicine and science know very well what many millions of heart-broken would be parents around the world know first-hand: To call all embryos “persons” flies in the face of spontaneous abortion, stillbirth and fetal death.

The Mississippi amendment is likely to pass, but it is unlikely to survive a court challenge. Yet don’t get complacent: several other states are already considering similar amendments, and the “personhood” movement is just one small part of a larger battle being waged by reproductive rights foes.