So 24 weeks is the magical line is it? As soon as he/she gets to 24 weeks he/she is capable of living outside of the womb, not a second later nor earlier?
Yeah, kind of. I understand your objection to magical lines, but we humans need to measure and categorise things. Such "magical lines" predominate our way of thinking. Why do you think people are considered as adults (legally and otherwise) when they celebrate their 18th birthday? Why not 17th? Why not 19th? How do we distinguish between petty theft and major theft? Why does judge X sentence criminal Y to Z years in prison? Why not Z years plus one? Minus two?
This is a universal problem. If we are going to eschew magical lines, we may as well tear human civilisation down with our own hands. The "magical line" argument cannot be evoked to outlaw abortion.