The concept of personhood is based on objective facts rooted in biology. If it were up to the decisions of others, then the Nazis should have been left free to act on their decision that Jews, gypsies, and others were Untermenschen, subhuman.
The decision regarding personhood belongs to the parents
That wouldn't follow even if we accepted that personhood is unrooted in objective reality. Why just the parents, when the whole of society is affected by the 40 million lives lost to abortion?
" The concept of personhood is based on objective facts rooted in biology. "
No, it is based on the intent of the creator, in this case it's the parents. The predominant biological system is the mother/parents and they have the sole right and sovereignty of will over all of their procreation related decisions.
"If it were up to the decisions of others, then the Nazis should have been left free to act on their decision that Jews, gypsies, and others were Untermenschen, subhuman.
The decisions of others disagreed and those folks thought it important enough to justify and kill nazis with gusto. Y'all going to start forcing women at gunpoint to nurture their unwanted pregnancies?
"That wouldn't follow even if we accepted that personhood is unrooted in objective reality."
Most every cell in a human body is human life and can give rise to a person. In order for a person to become a person the creator, at least the mother must make the decision.
"Why just the parents, when the whole of society is affected by the 40 million lives lost to abortion?
The whole of society is not effected. In the event the parents wait to long to decide, and effective contraception no longer applies, folks have a right to decide when parenthood applies by law in default as a standard. It's the same with the age of reason.