So the only objective scientific fact we have is that fertilized eggs are human (the adjective) - not that they are human beings (the noun).
Fetuses are uniquely different from born human beings in major ways. The most fundamental difference is that a fetus is totally dependent on a woman’s body to survive. Anti-choicers might argue that born human beings can be entirely dependent on other people too, but the crucial difference is that they are not dependent on one, specific person to the exclusion of all others. Anybody can take care of a newborn infant (or disabled person), but only that pregnant woman can nurture her fetus. She can’t hire someone else to do it.
Another key difference is that a fetus doesn’t just depend on a woman’s body for survival, it actually resides inside her body. Persons, by definition, must be separate individuals who operate independently of others. They do not gain the status of persons by virtue of living inside the body of another person - the very thought is inherently ridiculous, even offensive.
The normal meaning of human being implies a physical body of a certain size and shape with common attributes (excepting disabilities). Early embryonic forms do not share basic commonalities that define us as human beings. For example, zygotes and blastocysts are barely visible to the naked eye and have no bodies, brains, skeleton, or internal organs. Fetuses cannot breathe or make sounds, and they cannot see or be seen (except by shadowy ultrasound). They absorb nourishment and expel waste via an umbilical cord and placenta, not via a mouth and anus as do all other human beings. Further, fetuses are not just miniature babies. At various stages, fetuses have eyes on stalks, notochords (instead of spines), fish-like gills, tails, downy fur, distorted torsos, spindly legs, giant heads, and alien-looking faces. In fact, an early human fetus is practically indistinguishable in appearance from a dog or pig fetus. Finally, the fetal brain is not yet capable of conscious thought and memory (which aren’t fully actualized until two or three years after birth). But our complex brains are what set us apart from animals and define us as human beings. The brain is the seat of personhood.[6]
Anti-choicers also use the phrase “humanity of the fetus,” by which they may mean its biological human qualities, but it’s ambiguous, and purposely so. The word “humanity” implies compassionate human emotions and virtues, such as pathos, love, or kindness. The term is cleverly designed to elicit sympathy for a fetus, and assign it human-like qualities it simply does not have. The ability to feel joy, sadness, anger, and hatred are an integral part of our personhood, and we do not learn to develop such sophisticated emotions until we start socially interacting with others.
Besides the capacity to experience emotions, we generally think of personhood as possessing the qualities of intelligence, self-awareness, and moral responsibility.[7] Fetuses do not share these characteristics. On a more practical level however, the term “person” is really a legal and social construction. Persons enjoy legal rights and constitutional freedoms, such as the right to assemble, travel, protest, speak, and believe as they wish. Persons have birth certificates and social security numbers. Persons earn income, pay taxes, and vote, or they are registered dependents of those that do. Under this definition, it is an indisputable fact that fetuses are not persons. They are literally incapable of exercising legal personhood in any meaningful way. Although you could call a fetus a “potential person,” a potential person cannot have personhood rights either, in the same way that a 6-year old cannot obtain a driver’s license just because he’s a potential 16-year old. Potential persons have only potential rights, not actual rights.
So even though a fetus is biologically human, it’s definitely not a person (legally and socially), and it’s questionable whether it’s a human being (physically). Although we usually consider persons to be human beings as well, that’s not necessarily always the case. We could argue that intelligent animals like chimpanzees share some qualities of personhood with us, while a few human beings do not qualify as persons, such as brain-dead individuals.[8]Likewise, we could argue that fetuses are not human beings by virtue of their non-personhood and because they have unique physical qualities different from any born human being.
However, there is a wide divergence of opinion on the degree of “human beingness” of the fetus, and more pertinently - what its moral value should be. Biology, medicine, law, philosophy, and theology have no consensus on that issue, and neither does society as a whole. There will never be a consensus because of the subjective and unscientific nature of the claim. That’s why we should give the benefit of the doubt to women and let them decide - because women are indisputable human beings and persons with rights.
Does a Fetus Have a Right to Life?
Although fetuses cannot enjoy legal personhood, anti-choicers argue that fetuses do have a right to life that outweighs the right of the woman to control her fertility and her life.
Even if a fetus can be said to have a right to life, this does not include the right to use the body of another human being. For example, the state cannot force people to donate organs or blood, even to save someone’s life. We are not obligated by law to risk our lives jumping into a river to save a drowning victim, noble as that might be. Therefore, even if a fetus has a right to life, a pregnant woman is not required to save it by loaning out her body for nine months against her will.[9] In response, anti-choicers say that being pregnant is not the same as being a Good Samaritan, because the woman chose to have sex, voluntarily accepting the risk of pregnancy.[10] This argument is sexist and puritanical because it punishes women, not men, for their sexual behavior. Moreover, sex is not a contract for pregnancy - people have a constitutional right to non-procreative sex because of legalized birth control, which implicitly provides the right to have sex without reproducing.[11] Most abortions are caused by failed contraception anyway, but regardless, consent to sex does not entail consent to pregnancy, any more than consent to swimming implies consent to drown.
A fetus’ supposed right to life wouldn’t automatically overrule a woman’s right to choose anyway, which can be argued to have a higher moral value under the circumstances. The free exercise of one’s moral conscience is a fundamental right in our society. And since pregnancy entails profound physical, psychological, and long-lasting consequences for a woman - it is not a mere “inconvenience” - her freedoms are significantly restricted if she is forced to carry to term
prochoiceactionnetwork-canada.org/articles/fetus-focus-fallacy.shtml