"A Defense of Abortion" is a moral philosophy paper by Judith Jarvis Thomson first published in 1971.
Thomson presents the hypothetical example of the 'expanding child': Suppose you find yourself trapped in a tiny house with a growing child.
I mean a very tiny house, and a rapidly growing child—you are already up against the wall of the house and in a few minutes you'll be crushed to death.
Her argument has many critics on both sides of the abortion debate, You wake up in the morning and find yourself back to back in bed with an 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.
But, Thomson says, the person threatened can intervene, by which justification a mother can rightfully abort.
For what we have to keep in mind is that the mother and the unborn child are not like two tenants in a small house, which has, by unfortunate mistake, been rented to both: the mother owns the house.If we say that no one may help the mother obtain an abortion, we fail to acknowledge the mother's right over her body (or property).Thomson says that we are not personally obligated to help the mother but this does not rule out the possibility that someone else may act.The child on the other hand won't be crushed to death; if nothing is done to stop him from growing he'll be hurt, but in the end he'll simply burst open the house and walk out a free man.Thomson concedes that a third party indeed cannot make the choice to kill either the person being crushed or the child.As Thomson reminds, the house belongs to the mother; similarly, the body which holds a fetus also belongs to the mother.Again, suppose it were like this: people-seeds drift about in the air like pollen, and if you open your windows, one may drift in and take root in your carpets or upholstery.This analogy raises the issue of whether all abortions are unjust killing.Thomson does not support unlimited abortion rights.If the doctor refuses, then the woman is denied her right.To base the woman's right on the accordance or refusal of a doctor, she says, is to ignore the mother's full personhood, and subsequently, her rights to her body.