Just out of a need for accuracy, I think you have conflated two different concepts addressed by the Supreme Court in Roe v Wade. One was whether the unborn are considered “persons” for purposes of application of the 14th amendment proscription that no State may “deprive any person of life, liberty, or property, without due process of law.” (emphasis added). The Court concluded that the “unborn” are not “persons” under the 14th amendment. 410 U.S at 157 (“[U]se of the word [person in the Constitution] is such that it has application only postnatally.”)
The Court then specifically declined to determine the precise moment when “life” begins (regardless of whether that life constitutes a “person”), citing disagreement regarding that issue among philosophers, theologians, the medical profession and the States. 410 U.S. at 159 (“We need not resolve the difficult question of when life begins.”) There is little basis to question that their reference to “life” was solely in relation to “human” life, as that was the basis for the State of Texas’ argument that they were addressing. Id. (“Texas urges that … life begins at conception ….”) Nowhere in the entire decision does the Court opine on whether the unborn is “human” or “individual.” Thus, it could not be said that the Court agreed or disagreed with the notion that an unborn child was “fully human” or an “individual human life” at any stage of development. It explicitly chose not to answer that question.
What it did decide was that at the point of “viability” (defined as when a fetus is “potentially able to live outside the mother’s womb, albeit with artificial aid ….”)(emphasis added)(Id. at 160) the State’s interest in “the potentiality of human life” is such that it “may … regulate and even proscribe abortion ….” Id. at 163–65. Since the Court had explicitly decided not to decide when “life” begins, it’s use of the phrase “potentiality of human life” seems ill-chosen. However, given the context in which it arises and the discussion that precedes (in which the Court determined that the unborn are not “persons” under the 14th Amendment and that it would not decide when “life” begins) a more appropriate phrasing would have been “potentiality of becoming a person under the Constitution.” Essentially, the Court said that at the point where it became possible for the fetus to become a “person” (i.e. “potentially able to live outside the mother’s womb ….”) the State’s interest overcame the woman’s privacy right.
Again, this is just in the pursuit of accuracy.