Zygote to Embryo to Fetus to Infant: The Moral Debate about Abortion

Although the debate over abortion tends to become emotionally charged, there are some fundamental issues involved that can be examined from a strictly pragmatic perspective to help determine if abortion is ever morally permissible. These issues include most especially the precise point at which a fertilized human embryo can be regarded as a "human being" and therefore protected by the laws of the land as well as moral proscriptions against abortion. This nebulous line in the permissibility sand has been the source of much of the controversy concerning the moral permissibility of abortion, making its further examination timely and relevant today. To this end, this paper provides a review of the peer-reviewed and scholarly literature to determine what the experts have to say about the moral debate over abortion in general and at what point personhood is achieved in particular. A summary of the research and important findings are presented in the conclusion.

Review and Discussion

Although arguments against abortion vary in scope, intensity and reasons, the majority of opposition is related to the conceptualization of a fetus as a human being from the very start. In this regard, Joyce (1996) reports that on the one hand, "Most opposition to abortion relies on the premise that the fetus is a human being, a person, from the moment of conception" (p. 431). On the other hand, though, proponents of abortion argue that a newly fertilized zygote requires time to develop and assume the qualities that define a real human being. For instance, Joyce reports that such reasoning holds that, "The fetus is not a person from the moment of conception. A newly fertilized ovum, a newly implanted clump of cells, is no more a person that an acorn is an oak tree" (1996, p. 431). Because the terms are so central to the ongoing debate over the moral permissibility of abortion, the definitions of embryo, fetus, neonate and zygote are provided below:

1. Embryo: This term covers the time from fertilization to the end of week eight of gestation, after which it is known as a fetus.

2. Neonate: This is a child less than one-month-old (Merriam-Webster, 2012).

3. Zygote. In a normal pregnancy, the egg will be fertilized in the fallopian tube within 48 hours of intercourse; this fertilized ovum is known as the zygote and begins to cellular division process quickly (Etherington, 2000)..

Therefore, the very first physical manifestation of a sexual union is a zygote, followed by an embryo, fetus and then a fully formed human being; however, there remain stark differences of opinion concerning the exact developmental point at which the cells assume sufficient qualities to be deemed actual human beings (Joyce, 1996). Some authorities argue that by the third trimester, a fetus has developed to the point where it has assumed those qualities that define a person. For instance, Harrison emphasizes that, "Development of the brain to an operational level is a decisive indicator for sentience. Hence, third-trimester gestating fetuses deserve our respect from a moral point-of-view" (p. 313).

Others, though, place the time far sooner. In this regard, Joyce notes that, "Some say that the first signs of brain activity after about eight or ten weeks should be taken as the beginning of personhood, while others say that 'quickening' (when the mother can feel it move in her womb) is a sign that personhood has emerged" (1996, p. 432). This developmental stage, though, tends to differ when women have more than one child and gain experience in the pregnancy process. In this regard, Hursthouse reports that, "Many women who have borne children contrast their later pregnancies with their first successful one, saying that in the later ones they were conscious of a new life growing in them from very early on" (1992, p. 239).

These significant differences in individual experience suggest that this approach does not provide a viable point for demarcation. In fact, some authorities such as Joyce argue that the zygote itself is a person to the extent that it is worthy of respect, but it quickly becomes clear that other authorities do not share this belief. Some believe that the fetus only becomes worthy of respect at some later point, defined in such a wide variety of ways that absolutes are complicated and elusive. Rather than specify a trimester, for example, abortion opponents and advocates alike cite various points along the 280-day continuum as being the cut-off for permissibility, ranging from 1 second to birth and beyond, sometimes for months wherein the fetus becomes a neonate capable of survival outside the womb while in other cases the capacity for sentient thought is included just for good measure. For ease of analysis, the zygote argument does provide some useful guidance concerning permissibility of abortion since it defines the initial zygote conception as the demarcation point. Likewise, Harrison (1993) reports that the pro-life movement argues that "Even a zygote, at the moment of conception, is a 'person' and should be viewed as a citizen" (p. 185).

Balanced against this argument concerning when it is permissible to perform an abortion are the fundamental rights of the mother. For instance, according to Hursthouse, "If we suppose that women do have a moral right to do as they choose with their own bodies, or, more particularly, to terminate their pregnancies, then a law forbidding abortion would be unjust. Indeed, even if they have no such right, such a law might be, as things stand at the moment, unjust, or impractical, or inhumane" (1991, p. 234). The defining issue, then, appears to concern the exact point in time at which the fetus assumes sufficient human qualities to counter the rights of the mother if this argument can be made at all. For example, Joyce notes that, "Accordingly, if one is a developmentalist and argues that the fetus does not become a person until some later stage of its development one could conclude that it only becomes wrong to kill it after that stage has been reached" (1996, p. 432). For many women, though, the basic right control their bodies and their lives outweighs any inherent rights the fetus might have, and these basic rights become even more salient if the pregnancy threatens the health or even the life of the mother. Moreover, there are the other issues that impact the desirability of a given pregnancy such as instances of rape or incest, acts that are frequently cited by abortion proponents as being among the most important reasons for keeping the practice legal. In this regard, Hursthouse (1991) emphasizes that, "The morality of abortion is commonly discussed in relation to just two considerations: first, and predominantly, the status of the fetus and whether or not it is the sort of thing that may or may not be innocuously or justifiably killed; and second, and less predominantly (when, that is, the discussion concerns the morality of abortion rather than the question of permissible legislation in a just society), women's rights" (pp. 233-234).

The precise demarcation of the point at which fetuses become persons worthy of moral respect -- as differentiated from legal protection -- is clearly a difficult line to draw in the permissibility sand, and some authorities suggest that the line becomes some hazy as to be meaningless. In this regard, Hursehouse argues that, "One might say that this issue is not in the province of any moral theory; it is a metaphysical question, and an extremely difficult one at that" (1991, p. 234). Other authorities, though, maintain that although the argument is not cut and dry, there are some fairly obvious points at which abortion clearly becomes a morally indefensible act. For instance, Harrison believes that by the time a fetus becomes a neonate, the argument over permissibility is over and the jury is in. For example, Harrison writes that, "My own view is that infanticide is more morally dubious than late-stage abortion, precisely because the life of the neonate can be differentiated from the mother in a way not possible before birth" (p. 314). Societies that practice infanticide are on the same level, Harrison says, as those that allow late-term abortions. According to Harrison, "It is true that the position I endorse -- which differentiates a fetal life form worthy of respect, a human life, and moral personhood -- does not draw a sharp line between late-stage abortion and infanticide. But why is a sharp line necessary? A good society will seek to find ways to care for babies born into it, even though they are technically only 'potential persons'" (p. 314). When it comes to human beings, however, Harrison and her like-minded peers argue that late-term fetuses are completely worthy of respect as persons. As Harrison concludes, "It is morally wise to err on the side of imputing 'personhood' to a neonate, just as it is morally wise to impute respect to late-gestating fetuses" (p. 314)


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