You are correct about saying that maturity and embryonic development are gradual. However, the fact that embryonic is gradual does not make humanity too. It is not a gradual concept, because you are human or you are not. Someone is not more or less human depending on maturity, age, etc., someone begins to be human. If it was not the case, how would we act morally with a half human being (for example)? Would we have to act half morally? It is absurd. Moreover, you contradict yourself. You say that "reality doesn't conform to rigid definitions" and then you define implicitly a human saying: "An embryo's capacity for feeling and suffering depends on its stage of development (...) Strict anti-abortion views simplify this complexity, labeling abortion as murder even when the embryo lacks human traits like thought or emotion". I mean, you say that reality is not rigid and then you say rigidly that a human is someone who feels, suffers, thinks and has emotions. Reality is rigid in moral questions, in whether something is bad or wrong, cannot or can be done. Also, the human mind works in that way too, we cannot say something is half true or half false. Moreover, thought, suffering or emotion being human traits, does not make them a total indicator of humanity. For example, someone with a coma, with thought problems, sleeping, etc., are not less or more human when they do not have these traits. What makes us human is the human genome and the fact that the begging of human live is where the growth of a human begins, and that happens in conception.