When does human personhood begin?
Belief 3: It happens between
conception and childbirth
A newly formed zygote:
(commonly referred to as a "just-fertilized ovum")
The process of conception:
There is a general consensus that an ovum and spermatozoon are forms of human
life. People also agree that neither forms a human person.
People have different beliefs about the relationship between conception and
||Most pro-lifers believe that human personhood begins during the
||Most pro-choice advocates believe that personhood is attained later at
some stage of pregnancy, or even at childbirth.
At conception, a spermatozoon and ovum join to produce what is commonly
called a "just-fertilized ovum." The proper medical term is zygote.
A near consensus exists that:
A zygote is definitely alive: There is a general consensus that a
zygote is: "...biologically alive. It fulfills the four criteria needed to establish
- reaction to stimuli, and
The fourth criteria may appear strange. Zygotes can reproduce themselves
through twinning during the first 14 days after conception. That is how
mono-zygotic (identical) twins develop. After 14 days, a yellow streak
appears that will eventually develop into the spinal column. Twinning cannot
occur after that point.
A zygote has human DNA: In almost all cases, at the time of
conception, the 23 chromosomes from the ovum and the 23 chromosomes from the
spermatozoon combined to form a 46 chromosome DNA structure. The DNA is new,
unique and definitely human.
A zygote is a form of human life: A zygote is alive and carries
human DNA. Thus, it is a form of human life.
However, many pro-choicers believe that a zygote is not a human person. They view it as only a potential human
person. They believe that personhood develops at a later stage of pregnancy.
Resolving the conflict over abortion access:
Debates about abortion will never be settled until the precise status of a
human zygote is agreed upon:
||Is it, or is it not, a human person?
||If it is not a human person, there needs to be agreement on the stage of
pregnancy or delivery that the embryo or fetus attains personhood.
An agreement on these questions would go a long way towards resolving the
abortion conflict. However there would still be disagreements:
||If a zygote is considered a person, then abortion is an act of murder.|
||A case can be made for the criminalization of all abortions.
systems, except for that adopted by the Roman Catholic Church, would say that
an abortion would be ethical when a continued pregnancy threatens the woman's life.
||Some would argue that an abortion would be acceptable if continued
pregnancy would very seriously disable the woman.
If a zygote is not a person, then at least an early abortion involves
the killing of a non-person which has the possibility of someday developing
into a person. A good case could be made to allow women to choose freely
whether to have an abortion up to a time when personhood is attained.
Related essays in this section:
The color microphotograph of a just-fertilized ovum shown by permission from Dr. R. C. Wagner,
Department of Biological Sciences, at the University of Delaware, Newark, DE. They have many
other photographs at their Web page:
We thank Dr. Wagner for allowing us to reproduce these microphotographs.
Carl Sagan, "Billions and
Billions", Random House, New York NY (1997), Pages 163-179.
Copyright © 1995 to 2009 by Ontario Consultants on
Latest update: 2009-SEP-06
Author: B.A. Robinson