There's a scene from the 1991 film Star Trek VI: The Undiscovered Country, where one of the Klingon characters states, "Human rights. Why, the very name is racist."
She says this in response to the suggestion that people on planets throughout the universe have "human rights."
Since she is a Klingon, and so is not biologically human, she is keenly aware that claiming that she has human rights is problematic: it's like men saying that basic rights are men's rights, or the rights of men, and then acknowledging that women have them too; or a race of people defining rights in terms of their own race ("white rights"?) but then using that same terminology to describe the rights of people of other races ("black and brown people have white rights too"? No, we all have [or should have] the same rights, described in a general, non-race-specific way).
The concept of rights is not tied to any particular biology or species. So, yes, human beings have rights, but if there were Klingons or other non-human beings like them, they too would have those rights too. Since different species could have them—that's possible, or the concept allows it—that's part of the reason why it's unhelpful to think in terms of rights as human rights. That such beings (probably) don't exist is not relevant: suppose we called rights "less than 10-foot tall person-rights": the possibility that a greater than 10-foot tall person could exist is enough to show that this wouldn't be a good description for rights: we want a description that would apply to anything that, if it existed, would have rights.
Describing rights as "human rights" is problematic because the basis of basic rights is not tied to any particular biology or species. Why do both the human beings on Star Trek and the Klingons both have rights? What makes them have rights? It's not their species, since they are different species. The most obvious answer is that they both have rights because both these human beings and these Klingons are conscious, aware, thoughtful, feeling, communicative, and so on: they have minds of a certain type. In other words, they are persons. The human beings are human persons and the Klingons are non-human persons. (This is the basic reasoning given to think that many non-human animals have basic rights and are either persons or are person-like).
To take this discussion back to abortion, while (human) zygotes, embryos and beginning fetuses are biologically human, they are not much like the human crew on Star Trek or the Klingon crew, and they don't have the rights these crew members have. Fetuses are of the same species as the human crew, but the basis for rights isn't biology. So even though beginning fetuses are biologically human, they don't have the rights that human beings who are persons typically have, and they wouldn't have the rights that Klingons would have, if they were to exist. The language of "human rights" suggests that anything that's human has basic rights, but if we reflect on why anyone (or anything) has rights, or what makes something (or someone) have rights, we see that's naive: it's not just being of a biological category that makes something have rights.
People often assume (correctly) that human beings have rights. But they rarely think about why human beings have rights, or what makes them have rights. Fiction, and fictional persons who have rights, can help us understand why we have rights and help us understand why some biologically human organisms—like beginning fetuses—seem to lack what gives anyone rights. Thinking about actual persons, as well as possible persons—beings who, if they existed, would be persons—can help us understand personhood, and the basis of rights, which is essential for productive thinking about abortion.
P.S. An alternative view on personhood, which many critics of abortion claim to accept, is that persons aren't just beings that are conscious, aware, thoughtful, feeling, communicative, and so on (and there are ways to explain why sleeping people and people in comas remain persons even though they can't currently think, feel, etc.); it's that any kind or type of being that is conscious, aware, thoughtful, feeling, communicative and so on is a person. So, advocates of this view might say that although a fertilized human egg and a fertilized fish egg (or beginning fetus, if you don't like the egg example) seem very similar, a fertilized human egg is this type or kind of being and so is a person, whereas the fish egg is not.
Some fair questions are this: why accept this proposal for what persons are? And why reject this proposal?
One quick reason to reject this proposal is that if being the kind of being that is conscious, aware, thoughtful, feeling, communicative, and so on makes anything (like an embryo) an actual person, then—since those characteristics also make someone responsible, autonomous, praise and blame-worthy—so on that would also seem to make that embryo actually responsible, autonomous, and praise and blame-worthy. But embryos are none of that, so being a "kind" of being doesn't mean you have the actual characteristics that result from actually being that being: e.g., being the kind of being that's a person, and the kind of being that's responsible and so is different from being a person and being responsible. Here's some on that; more will be posted later.
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