What are the counterarguments against abortions in rape cases to the Thomson paper?

Question

Came here from Christianity StackExchange

"A Defense of Abortion" (Thomson):

You wake up in the morning and find yourself back to back in bed with an unconscious violinist. A famous unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist's circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. [If he is unplugged from you now, he will die; but] in nine months he will have recovered from his ailment, and can safely be unplugged from you.

It is said later that:

Critics of Thomson's argument generally grant the permissibility of unplugging the violinist, but seek to block the inference that abortion is permissible by arguing that there are morally relevant differences between the violinist scenario and typical cases of abortion.

But it is unsourced. :(

What are the morally relevant differences?

I did google responses to the Thomson paper, but they were either too wordy, too disorganized or incomprehensible. All I remember finding was this one paper about how unplugging is different from poisoning or something, but then it had too many words and now I can't find it.

Answer 1

Wikipedia, which is the source of the quote, in another article also lists the typical objections, with references, which arguably point out moral distinctions.

The responsibility objection: kidnapping makes the violinist scenario analogous only to abortion after rape, in most cases the intercourse was voluntarily, so the woman herself caused the baby to need her body.

The stranger objection: embryo is the woman's child, unlike the violinist.

Let die objection: abortion kills the embryo while unplugging the violinist only lets him die, so abortion is premeditated murder, but with unplugging death is a foreseeable but unintended consequence.

Boonin argued more recently (Thomson's paper is from 1971) that the above distinctions are either morally irrelevant, or do not apply to abortion in their moral aspect. Here is a critique of that due to Beckwith.