Why should the wonan’s Right to bodily autonomy post 24 weeks justify the termination of the foetus if it is capable of being delivered alive and surviving?
Because to deliver it alive is to deny the woman's bodily autonomy. For those of us who prioritise the woman's bodily autonomy, the fetus has no right to life.
"The pro-choice (anti-life) argument is one born out of a primitive mediaeval belief (or otherwise deliberate unwillingness to accept basic scientific reality) that once a male sperm has fused with a female egg, it has created a human life - and that life doesn't suddenly magically begin the moment a baby first sees daylight" ?
This is a misrepresentation both of medieval thought and of modern pro-choice positions. As others have argued above, even if we recognise the fetus as alive, it does not have equal status with the pregnant woman.
Most ethical thought wrestles with liminal points: pregnancy and end of life situations and persistent vegetative states etc. Questions about the meaning of life at the limits of life are not easily resolved, especially when it comes to determining when and how humans should intervene in the realm of God/the course of nature/ the expectations of society. It's difficult because it's inevitably complex.
My position is pro-choice because I think interventions ought to prioritise women over fetuses. I can see the opposite position but I think it is wrong because I reject the moral absolutism of the pro-life/anti-choice position. People who hold that position seem to see my position as a dangerous kind of slippery slope that could lead to infanticide.
It's important to me to argue for a pro-choice position because when I look at what is happening to women's reproductive rights in the USA I worry that any philosophical and legal position that affords personhood to fetuses is a position that (perhaps unintentionally?) severely curtains women's freedom, rights and health.