One of the callers referred to the foetus as a parasite. Some years ago an article in This Rock Magazine dealt with this assertion.
Volume 15, Number 5
X Marks the Spot
Abortion is legal. Infanticide is illegal. If a woman wishes to terminate her pregnancy at any time before birth, she is said to have "exercised her right" to do so. If she wishes to terminate her child’s life at any time after birth, she is viewed as a killer and prosecuted as such. Why the difference?
The answer must be that there is a quality or set of qualities (let’s call it "x") that all newborns have and no preborn infants have that makes newborns worthy of protection by the law and preborn infants unworthy of such protection.
So, the question is: What is x?
One of Mr Kidd’s replies:
X is the fact that a fetus is a symbiont (parasite)."
As always, you should first ask your interlocutor to define his terms. Is he using symbiont in the scientific sense or a more general sense? In either case, there are several strategies you can use.
First, the term symbiosis is generally defined as a relationship between two or more organisms of different species in which one or more benefit from the interaction. Note that it refers to different species. Mother-child relationships—whether prenatal or postnatal—are not regarded as symbiotic in the strict sense of the term.
Second, there are four types of symbiosis:
mutualism, in which both partners benefit;
commensalism, in which one member benefits while the other is unaffected;
parasitism, in which the parasite benefits while the host is harmed; and
amensalism, in which one member suffers while the other is unaffected.
If a fetus is a symbiont, which of the four categories does it fit into? Not mutualism—ask any nine-month-pregnant woman if she has benefited from being pregnant! Not commensalism or amensalism, because it cannot be said that either the fetus or the mother remains unaffected.
But does parasitism fit the bill? The mother certainly experiences discomfort (morning sickness, aching back, etc.), but do these inconveniences qualify as being "harmful"?
If he is creative, your opponent may choose another gambit: creating a fifth category of symbiosis. But it would be apparent that anyone who did this was doing it for the sole purpose of justifying abortion.
Furthermore, if a fetus is a parasite before birth, does it continue being one after birth? Your opponent will be forced to say no, because if a newborn is a symbiont, then newborns would be as expendable as fetuses are. Why is an infant not a symbiont? How has the relationship changed, beside the fact that it is now outside the womb rather than inside it?
Furthermore, even if it could be established that a fetus is a symbiont, it is not clear why a symbiont is expendable but a non-symbiont is not. Does symbiosis somehow degrade your status as a living being? Are symbionts necessarily of less worth than other living things?
Of course, your opponent could be using the term symbiosis in a general sense, arguing merely that a fetus is similar to a symbiont, to which you can respond: Yes, that’s very observant of you. But it does not follow that a fetus is expendable simply because it exhibits traits similar to symbionts. After all, newborns are also symbiotic in many ways, but we protect them from being killed nonetheless.