"Exatron: of course they are different, the question is material difference, i.e. why should this particular difference mean A can be killed and B cannot."
A (black people, women, historically oppressed groups, etc.) has cognition and volition. It doesn't require the use of another person's body to function. There is no violation of rights involved should they continue existing, simply because of their continued existence. B is entirely dependent on direct use of another person's body irrespective of that person's consent. Without that consent, their continued use of that person's body is a violation of that person's rights.
"You make a fair argument about cognition, thinking and feeling, although the point about living outside the womb is flawed because a baby can only live outside the womb if its survival needs are met by someone else - inside or outside in both cases the intervention of another is required."
No potential violation of rights is involved in the support of a baby, rather unlike the gestation of a fetus.
"turning back to the thinking/feeling thing, I'm afraid i don't really see why that should be the arbiter?"
It makes it clear that in cases of bodily rights, there is no clash at all. Why should rights of any kind be ascribed to non-sentient, completely non-autonomous things?
"To be clear, my argument is that a fetus, embryo, whatever, is indeed human and is entitled to human rights just like you and I, specifically the right to life."
Why?
"However, I don't think I will ever agree with you that full term abortions should be permitted at will."
I'll never understand the obsession with late term abortion restrictions. Later term abortions tend to make up about a 0.2% of all abortions, and are done exclusively in the case of severe health issues or extreme fetal abnormalities. However, this fixation provides endless cover to pro-life lunatics who use these "reasonable restrictions", combined with roadblocks and barriers to access, to prevent women from obtaining abortions until the supposedly reasonable restrictions ban it.
Late term abortion restrictions are very much like Voter ID laws; a solution seeking a problem. Such laws provide enough ammo for pro-lifers that they're likely to end up killing/permanently disabling more women via roadblocks (if there were no restrictions on abortion, TRAP laws wouldn't have a legal leg to stand on) until the date is passed than they ever will save late term fetuses that Evil Harlots kill for the sake of sheer sadism.