First a few comments. An unwanted fetus is a parasite for the simple reason that it lives off of its mother (host) and returns nothing. A wanted fetus is not a parasite, but rather a symbiote. It too lives off of the mother, but it returns something. An infant is always a symbiote. It lives off its parents, but returns an emotional bond. If such a bond does not exist (the infant is not wanted) the child may be adopted by another couple, for which the relationship will be symbiotic.Originally Posted by Katie '85
So a fetus is not exactly the same as infant, the term parasite can apply in a logical and consistent fashion.
However you are right that the crux of the issue has nothing to do with whether or not the fetus is a parasite. Does the host have the right to expel a parasite if it is human? After all we have laws that require parents to support their children. As a society we support the aged and infirm even though they may well function as societal parasites. We prosecute those who would violate their rights as human beings. So an excellent case can be made that if the fetus is a human being then it is entitled to the protection of the state and abortion should be illegal.
To look into the status of fetuses, a number of thought experiments are useful. The first is for all practical terms there is hardly any essential difference between a fetus just minutes before birth and an infant just after birth. The proscription on late-term abortions reflects this observation. At some point a fetus become so baby-like (including being able to live as a baby if born prematurely) that is hard to see how it inherently is different from a baby as far as its rights are concerned.
But there is the other end. If fertilized eggs (embryos) are people, then in vitro fertilization procedures involve mass murder on a routine basis. In fertility clinics millions of embryos are imprisoned within freezers and considered the property of their parents. Specifically if the parents don't wish to have any more children these embryos (people) are simply killed. Should all couples who have undergone in vitro fertilization be charged with murder?
If not, why? How can treating embryos as livestock whose lives may be sacrificed at the whim of their owners be justified if these embryos are human beings? The consensus amongst most Americans is that couples undergoing in vitro fertilization are not mass murderers. Embryos simply are not exactly equivalent to babies or children in terms of humanness.
A morning after pill that blocks attachment of an embryo, resulting in it being flushed out of the body to die, is exactly equivalent to the introduction of five embryos to hopefully produce one baby during in vitro fertilization. The status of the embryos that don't attach is the same as those in the freezers at fertility clinics.
At some point in its development the embryo becomes sufficiently baby-like to no longer be considered as equivalent to the embryos in the freezer and to instead to be more like a newborn infant. And at that point, the fetus would become human. Where that line would be drawn will be different for different people. But it seems clear that for the population as a whole, on average, it is well after conception, but well before birth.
There exist logically-consistent extremists on both ends. Those who believe they must support the right to abort an 8 month fetus in order to preserve choice, and those who are prepared to condemn infertile couples whom have undergone in vitro fertilization as murderers in order to be consistent with their belief that life begins at conception.
On the other hand, many people are not logically consistent about the issue.