The morality of any act must be evaluated according to the moral determinants — the moral object, the purpose or end, and the circumstances. The history and origin of a physical thing used in an act can be relevant to the consideration of circumstances, but that a thing has an illicit origin does not mean that it should be discarded or that it cannot be used in a good act. An illicit origin by itself does not determine the proper end of a thing.

For example, suppose I steal a couple of dogs. I steal a male and a female because I want them to breed, and I do breed those dogs. My reason for doing this is simply to turn a profit so that I can have food and shelter. So, my actions have produced a litter of dogs for whom I orchestrated their coming into existence by illicit means. I did things that were objectively immoral for the sake of doing something that had a moral end.

Once this litter of puppies exists, the right thing to do would not be to take these dogs and slaughter them simply because they are from an illicit origin. History and circumstances alone do not determine anything. The fact is… the current reality is: these dogs now exist. So, now that they exist — even though it should not have come to this, even though this situation is a result of wrongdoing — what are we to do? This, the new set of circumstances, is now the reality. Now that we have this reality, the question of what we ought to do is also new. Hence, this is a brand-new moral evaluation. What any person might do to these dogs is subject to its own moral evaluation, and the fact that the dogs were, in a sense, illicitly conceived is all but irrelevant to the question of what should be done with the animals.

If it so happens that one day we are faced with the reality of a woman carrying a child who is a clone, the fact that many objectively immoral acts led to that result will do nothing to mitigate the reality that the clone is a human person with dignity and purpose.

It is not inappropriate or illicit to benefit from a set of circumstances that have arisen only because of bad actions, or because of immoral actions. Even though a good end never justifies evil means, good can arise from evil. The supreme example of this is that the crucifixion of the Son of God should not have happened. It was an objectively evil act to crucify Jesus Christ, an innocent man. It is objectively evil to murder an innocent man. However, now, the reality is that because it happened there is an opportunity to benefit which became available to me that would not now be available were it not for the objectively evil actions of others.1

So, to say that I should not do what I could do to be a beneficiary of something that is only existent now because it came to be by illicit means, would mean that I should not worship Christ and become a member of his Church, due to the fact that I then benefit from the evil done to him. As another example, consider a woman who is raped and conceives a child. She carries the baby to term, and she gives birth to a little girl. The girl grows up and wants to marry. If we subscribed to the idea that it was inherently immoral to profit from evil done by others then it would be necessary to say that nobody could marry that girl, because “that child shouldn’t even exist.” But the reality is that the child does exist. That child has dignity and purpose, and none of that is diminished at all by the fact that she was conceived in rape.

We could also point to the pyramids and say that nobody should be permitted to marvel at them or investigate them since they were constructed by slave labor. Or we could say that the roads in Rome must be torn up because they too were built by slave labor under horrendous conditions. The examples are on the extreme end of the spectrum, but they manage to make the point clear — namely, that there is no longer a chain of moral determinants. (If slave labor still existed in Rome, then there could have been a chain of moral determinants.) Each and every act must be weighed individually; each act has its own object, its own intention (end or purpose), and its own set of circumstances.

In the case of the rubella vaccine, we begin a moral evaluation by going all the way back to an abortion that took place in Sweden in 1962. It was an elective abortion; the parents decided they simply did not want any more children. They did something objectively evil, and they had the pregnancy terminated. The doctors who performed the abortion, they did something objectively evil in ending the child’s life. At that point, they did something else. They handed over the child’s remains to another group of doctors who dissected the corpse. This second group of doctors removed the lungs and sent them to the Wistar Institute in Philadelphia to be used by the doctors there. One doctor in particular, Dr. Leonard Hayflick, chose to attempt to use those lungs to produce a human diploid cell strain. He was successful, and the resulting cell strain is known as WI-38.

Dr. Hayflick subsequently distributed the cell strain to a great many researchers, one of whom, Dr. Stanley Plotnik, utilized WI-38 as a growth medium for the rubella virus. By infecting the WI-38 cells with the virus, RA 27/3, and allowing it to replicate at reduced temperatures, Dr. Plotnik successfully produced an attenuated virus that forms the basis for the rubella vaccine in widest use today — the only one now approved for use in the U.S.

We already know that the act of aborting the child was objectively evil, but what about the act of dissecting the child’s remains? The moment that the abortive act was complete, the second group of doctors were presented with a new situation, not unlike when a murdered man is brought into an emergency room. Provided that the man or his family had given consent, there is nothing objectively wrong with a doctor harvesting the victim’s organs for licit uses. We know, as did those secondary doctors, that with abortion legal in Sweden the abortion was going to happen, and they had no say in it. Is it possible that they were cooperating with evil? Yes, and it could have been formal or immediate material cooperation, which would make them culpable. On the other hand, their cooperation, if it existed, might have been acceptable, which is to say, it might have been mediate material cooperation. The fact is, however, that we do not know whether the secondary doctors cooperated illicitly with the evil of the doctors who killed the child.

So, was the harvesting act of the secondary doctors immoral? Possibly, but we cannot condemn the act with certainty, because the object of the act was not evil, and we do not know that the doctors had evil intentions.

Sending the lungs to America is another act that cannot certainly be condemned. But what about Dr. Hayflick’s creation of a cell strain? The moral object of that act is not inherently evil. There does exist a possibility that Dr. Hayflick cooperated formally in the act of the abortion by the first doctors, but that is a fairly remote possibility and one that we cannot establish. Thus, we have no certain grounds upon which to condemn Hayflick’s creation of the cell strain WI-38.2 Without a clear evil in the creation of the the cell strain it is impossible to argue that the distribution itself of the cell strain was immoral. Even if the act of creating the cell strain was immoral, and the distribution along with it, the act of receiving the cells was not objectively evil.

Finally, one must evaluate the history of the rubella virus that was cultured in WI-38, as well as the very act of culturing the virus. For the sake of brevity, I will note that RA 27/3 was isolated from the tissue of a child who was aborted because the mother had contracted rubella. The subsequent series of moral evaluations of the multiple acts that led to the eventual culturing of the virus is similar to the evaluations that followed after the abortion in Sweden — that is, they cannot each be certainly condemned. Most of the acts were not objectively evil, and too little is known about the intentions of Dr. Plotnik and his team members. Weighing circumstances, the third determinant, in this case is largely a prudential consideration: The material to create an effective vaccine was of illicit origins, but rubella was pandemic and destroying many lives.

The point of all of this is simple: it is possible and licit to approach a situation where bad has been done by others and to respond by using the products of evil to produce something good. This does not mean that parents are morally obligated to give their children the rubella vaccine, atleast not in the current environment, but that could change if vaccination was necessary to quell a pandemic.3 It does mean that those parents who choose to vaccinate their children are not cooperating with the evil of abortion. I can no more cooperate in the abortion in Sweden that happened twenty years before my birth than I can cooperate in storming the beaches of Normandy on D-Day.

If we trace back far enough, we can always find an evil connection to something. Is it likely that some dollars from my purchase of the MMR vaccine will end up enabling someone who works for Merck to do something evil, like purchase pornography? Sure, but that’s equally true when I buy a pizza. More importantly, is it likely that my dollars will contribute to a repeat of the evil committed that brought about the rubella vaccine? No, as a matter of empirical investigation, it is highly improbable. Human diploid cell strain creation is rare, and it is unnecessary for the continued manufacture of the rubella vaccine.

The present acts that contribute to maintaining the WI-38 cell strain, including the remote and mediate act of purchasing vaccines produced via the cell strain, are not necessarily immoral either. Of great importance is the fact that these acts do not promise to contribute to future abortions. In fact, the use of the cell strain can be a way of upholding the aborted child’s dignity of purpose. However, given that the child from whom WI-38 was derived was the victim of murder, one could refrain from use of WI-38 in order to uphold the child’s inalienable dignity and right to life that was violated. Both courses of action are morally licit, at least until the Magisterium determines otherwise.

What the Catholic faithful ought to know:
1) Use of the rubella vaccine found in the MMR vaccine does not constitute cooperation with any past evil act.4
2) Use of the MMR vaccine to vaccinate your child might constitute cooperation with evil, but not with abortion. Remote mediate cooperation with evil would not necessarily be diminished by using a vaccine cultured in, for example, a rabbit cell strain.5
3) If you choose to use the MMR vaccine, your conscience need not be bothered by the origins of the cell strain used in the vaccine’s creation.
4) If you believe it is wrong to use the vaccine, then you would be sinning by violating your conscience if you used it. But you must still recognize that, as of right now, all Catholics are free to use the rubella vaccine.


  1. Even if we agree with Sts. Bonaventure and Anselm that the expiation of our sins needed to occur in this manner, still, the persons responsible for Christ’s death committed a gravely evil act. (Of course, we know that all were forgiven for that offense.) 
  2. Admittedly, Dr. Hayflick is now known to have no objections to abortion, and it is possible that he expected his cooperation to promote abortion. Yet there is doubt surrounding that idea because a great many abortions have been avoided as a result of his research. Although ends don’t justify means, it’s possible that Hayflick sincerely believed that his work would prevent abortions. 
  3. It could be argued that a moral obligation exists also when unreasonable abstention from vaccination will likely contribute to substantial risk of a pandemic. And this might soon be realized with the numerous recent outbreaks of measles. 
  4. Yes, I am aware of what the PAL said in its letter from 2005. However, the authors clearly failed to logically apply their expressed criteria for material cooperation: “Material cooperation can be further divided into categories of immediate — direct — and mediate — indirect — depending on whether the cooperation is in the execution of the sinful action per se, or whether the agent acts by fulfilling the conditions — either by providing instruments or products — which make it possible to commit the immoral act.” By using a vaccine today, do I thereby “fulfill conditions which made it possible” to abort a baby 45 years ago? No, that question is nonsensical. One cannot fulfill conditions today for a thing that occurred in the past — neither the abortion nor any other immoral act that led to the current reality. 
  5. Since an agent cannot cooperate with evil done in the past, purchasing a vaccine that was cultured in rabbit cells produced by a company who spends a great deal of money on evil would probably — every specific act needs a proper moral evaluation — be worse than purchasing one produced using the WI-38 strain by a company that is more ethical. This is entirely hypothetical, however. 

The opinions expressed by the DPS blog authors and those providing comments are theirs alone; they are not necessarily the expressions or beliefs of either the Dead Philosophers Society or Holy Apostles College & Seminary.