Defining personhood

The use of foetal tissue for research purposes is an area of great controversy. A crucial factor is whether or not the human embryo is also a 'person'.

• The completion of the human genetic input is already complete at the single cell stage.
• Full differentiation is not complete until early adulthood.
• Both genetic and developmental individuality begin at fertilization.
• Any parallel between "brain death" and "brain birth" is scientifically invalid.
• The arguments used to define personhood are not grounded on scientific fact.

Personhood, Abortion and Stem Cell Research

It's at the cutting edge of medical science. The hope that stem cell therapy may lead to cures for dreaded ailments such as Parkinson's and Huntingdon's disease and diabetes.

One area of stem cell research is controversial. Cells taken from early embryos are believed to hold more promise because of their greater potential for adapting into different types of tissue. (A problem is likely to be tissue rejection, which is not the case when the stem cells are taken from a person's own cells.)

Critics say that early embryos are small human beings ? not just a "bunch of cells" to be harvested. The destruction of these embryos, they say, is unethical, unlike "adult" stem cells taken from umbilical cord blood and bone marrow.

A crucial factor in the debate is what the scientific evidence reveals.

The case that embryos are human persons

Human embryologists know that by the end of fertilisation, the 23 chromosomes of the sperm, and the 23 chromosomes of the ovum, have combined to produce a human being, possessing 46 chromosomes? the kind and number specific for the human species.

Many writers using scientific data as their starting points argue that ?personhood' appears at different biological marker events during the development and growth of the human embryo.

Therefore, it is because all human infants (newborn as well as foetal) do not actively exercise rational attributes or sentience that they are all not persons, according to Singer and his colleagues.

Quoting directly from a PBS interview with Singer:

"Well as I used the term 'person' -- a 'person' is a being who is capable of anticipating a future, having wants and desires for the future, which are cut off, thwarted, if that person is killed.

And I think that is generally a greater wrong than it is to kill a being who has no sense of existing over time. And that might be, for example, a chicken has no sense of existing over time. And that, I think, is one reason why it's normally worse to kill a human being than to kill a chicken.

But also, of course, newborn babies have no sense of their own existence over time. So, it's not equivalent. Killing a newborn baby -- whether able-bodied or not -- I think, is never equivalent to killing a being who wants to go on living."

Brain-related criteria

Others argue for some sort of brain-related criteria ? either "rational attributes" (self-consciousness, autonomy, loving, willing, relating with the world around one, etc.) or "sentience" (the ability to feel pain or pleasure).

It is conceivable that patients may come to be regarded as "useless eaters", or even fall prey to the allocation of scarce medical resources cuts. When it comes to surrogate decision making for incompetent patients, there may be some doubt as to whether decisions will be made in their best interests ? or of the hospital.

When conflicts arise concerning these patients, there is a danger that they will be seen by some of those in the mediation process as "non-persons" whose "quality of life" does not demand that they be given equal respect and equal medical treatment.

This in turn can lead to poor quality health care both on a routine and acute basis, and abuse in medical research.

(Adapted from a paper by Dianne Irving, M.A., Ph.D., Assistant Professor of Philosophy and Bioethics at De Sales University, U.S.A.)

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