Looks like you're rebutting an argument I didn't make. You changed my argument from the serious problem of principles regarding bodily autonomy being inconsistent with pro-life philosophy, to something something about line-drawing. I'm not going to address arguments against views I did not state nor hold in the first place.
The view is implicit in your argument. If a fetus is recognized as a person at some point in the pregnancy before birth, then the mother owes a duty of care to that child at that point -which means she can't take an action that would harm it. During pregnancy, due to the natural, unalterable relationship between the mother's body and the child, the mother's duty to care means that she must allow the child to develop in the womb. IOW, the fetus' right to live usurps the woman's right to control her body. That view is not in conflict with
Roe or any other ruling I'm aware of.
You need a strong argument explaining how a duty to care logically implies that strangers can use your blood and organs without your permission.
It doesn't. We don't have a duty to care for strangers. I argue that a parent has a duty to care for their child.
Child support is based on the view that raising a child is an enormous burden which would be unfair to place on one parent,
I would say it's based on the view that the duty of a parent supersedes the parent's own self-interests. A parent cannot simply walk away and abdicate their responsibilities. They can't kill their kid because they don't want them anymore.
but it's not clear that this view actually implies that someone may use your blood and organs without your permission as no family court as ever ordered fathers to donate kidneys and lungs for the sake of saving their children's lives.
The mother isn't donating kidneys and lungs or even blood, therefore the analogy is not that strong.
Errm, yes, the mother is giving up her organs to a person which is literally attached to her placenta, her blood supply, her cardiovascular system, residing in their body, and cannot be separated before birth without surgery.
Again, she isn't giving up her organs in any sense of the word. Her organs remain intact and fully functioning for her needs. The placenta is not exclusively the woman's organ; it's more of a shared organ with most of it arising from the fetal tissue. Thus, it could be argued that the woman doesn't have the right to remove the organ the fetus needs to survive. Again it all comes down to personhood.
And that's a problem. Pro-lifers do not accept the implications of a view which says another person's medical need for blood and organs supercedes the consensual use your blood and organs.
I would say that's true for strangers but not for one's own children. If a parent was a match for one of their children, I would expect the parent to happily donate whatever the kid needed. A bit of Googling did not turn up any cases where a parent refused to do so. Thus, it could be that a law is not necessary to compel donation from parents.
Not even the most ardent pro-lifer would never argue that a parent be restrained and forced to donate bone marrow to their children without the parent's consent -- even though that scenario is a logical consequence of their view.
I have not seen that come up before. We don't know what a pro-lifer would think about such a scenario. For my part, I would like to see a parent who refused to donate an organ prosecuted for failing in their duty to care, unless such donation was medically inadvisable. I can't force them to donate, but I can certainly punish them for taking an action that caused harm to their kid.
Pro-lifers cannot avoid that consequence without completely contradicting their philosophy which says that the only difference between a born and unborn child is their location in relation to their mother, which they argue is not a morally meaningful distinction. If an unborn child's medical needs allows it to use it's mother's blood and organs without mother's permission, then that principle logically carries over to born child whose medical needs allow it to use mother's blood and organs without her permission. Erg,: a moral duty forcing mothers to give up their organs, blood, and bone marrow to meet a born child's medical needs.
I think such a moral duty does exist even if there isn't a legal duty. A parent has a duty to care for their child and not take actions which will harm them. This starts in the womb and extends until the child reaches adulthood. I would even say that a parent has a duty even through adulthood. Again, I don't see laws being crafted to enforce this duty, but it is certainly a moral duty, IMO.
If pro-lifers accept this dystopian consequence, it would be consistent within their own ethical framework.
I don't find it dystopian. I cannot imagine a parent who would not willingly and happily donate whatever the kid needed to survive. I would give up my life to allow my kid to live longer.
But they often do not accept that consequence. They behave as if a mother's duty to give up their blood and organs to meet their child's medical needs is logically dependent on the location of the fetus. So moral consideration of a child's right-to-life and right to life-saving blood and organs is conditionally dependent on their location relative to their mother. If birth is a morally irrelevant change in location between born and unborn children, how did we end up with principles that paradoxically imply birth is change in location and moral consideration?
I don't think it has to do with location. It has to do with the personhood of the fetus. If the fetus is not a person until they are born, then there would not exist any duty to care for the fetus. I believe the fetus is a person at least beginning with viability. Thus, the mother has the duty.
I am honestly trying to see how pro-life principles tie together into a coherent ethic, but it's just a frustrating experience. Their principles neatly explain why a stranger can make claims on another person's blood and organs without their permission, but do not address the moral rats nest of implications that follow.
I think you need to address the actual arguments of pro-lifers and not the straw men you are creating. I think you would find more of them do indeed put a heavy moral burden on parents when it comes to the care of their kids. I know I do.