Erroneous.
Science has declared that a unique individual human being begins to live at the moment of conception.
The dictionary, as we all know, foundationally defines "person" as "a human being", and no other definitions of "person" ever override that.
Thus rational common sense long ago learned how to correctly apply the terms, such as "personhood", by appealing to unconjecturable definition and logically applying that to newly discovered circumstances.
Thus when science discovered a few decades ago that a human being begins to live at the moment of conception, the fact that a human being was discovered to be present at conception, logically attributed to that person the status of "personhood".
It really is that accurate and simple, Dawkinsrocks.
You are not wrong in your ascertation that, in effect, a newly conceived person has no brain.
But that's scientifically irrelevant with respect to being a person, a human being.
Science, as the opening and subsequent posts have confirmed, does not care that a person has yet to develop their brain for that person to be a unique individual human being, a person.
Your "no brain" sophistry is rejected by science itself.
Absolutely false.
The realities of rights, that I linked you to previously, presents the truth about rights, and that truth is that the right to life is foundational and it applies to all people, no matter how old they are.
Your attempt to deprive the newly conceived person of that person's right to life is an egregious example of making an error from an appeal to the bias of ageism.
Your erroneous implication is inaccurate and irrelevant.