You have likely heard this line of reasoning from earnest pro-lifers before. (Snopes.com even has an example listed as "glurge".) I saw a meme from a Christian pastor on Facebook last week that echoed the same kind of speculative story.
The logic goes something like this: You should be pro-life because you never know if you've aborted the next Einstein, the next Beethoven, the next Martin Luther King, Jr., the next Pasteur or Salk, etc. What if you aborted the curer of cancer or AIDS?
The motivation is understandable and the underlying reasoning is sound: abortion, which does immediate harm to unborn children and many of their mothers, does unseen future harm to families, communities, and the world.
But I don't think Christians should use this argument against abortion, and here's why: It assigns value based on (presumed) accomplishments. It is a utilitarian argument -- assigning intrinsic value based on one's "utility" (usefulness) -- and it is utilitarian arguments that are best suited for pro-choice arguments, not for pro-life. In any event, those contemplating abortion are already employing utilitarianism in their thinking. e.g. "This child will have a poor life, so it is best to prevent him from experiencing it." "This child will interfere with my plans for the future, so it is best to terminate my pregnancy until I am really ready."
The reasoning also fails to consider that we are actually right now perilously close to abortion based on predictive value. In America, it is dangerous to be an unborn African American. In China, it is dangerous to be an unborn girl. As fertility treatments become more advanced, parents have potential some day of "custom designing" their babies, right down to hair and eye color. What would be done, then, with "error" babies? They are thrown away like garbage. And of course abortions of unborn children with Down syndrome and other conditions disagreeable to their parents are commonplace already.
What happens in the day, rapidly approaching, when technology can show us that a child will be mentally advanced? What happens to the mentally "just average" fetuses then? Some are asking gay rights advocates if they would remain pro-choice if in the future that elusive "gay gene" they keep searching for could be found. What if moms wanted to abort fetuses who test positive for this gay gene?
No, the utilitarian view of human life has no place in the Christian worldview, and we should give it no place in our efforts against abortion, as powerful or convicting as we think those arguments are.
The biblical grounds for the pro-life argument have nothing to do with a person's "usefulness" to a family or society. The Bible calls us to the pro-life position based on the reality that all persons are made in the image of God, that God has created us equal, and that therefore all life is precious, whether a person cures cancer or gets cancer, wins an Olympic medal or a Special Olympics medal, can compose like Mozart or sings like Roseanne Barr.
Suppose we could save the future Einsteins and Beethovens from the abortionist. It would still be as tragic and sinful to have otherwise commenced with the offing of future stay-at-home moms, truck mechanics, and janitors. You know, all the "ordinary people" of which there are many more than the so-called extraordinary people. More boldly put: abortion is wrong, whether you happen to be aborting the next Mother Theresa or the next Adolf Hitler.
Pro-lifers, let's not play that game. Leave utilitarian arguments to the self-appointed engineers of utopia. Let's be Christians living in the kingdom of God instead.
"If I have rejected the cause of my manservant or my maidservant,
when they brought a complaint against me,
what then shall I do when God rises up?
When he makes inquiry, what shall I answer him?
Did not he who made me in the womb make him?
And did not one fashion us in the womb?"
-- Job 31:13-15