"These cell lines are maintained in such a way that they have an indefinite lifespan, providing all the cells needed for the production of vaccine and for some other uses. It is said to be unlikely that any additional human cell lines will be produced or needed for two reasons. First, for scientific purposes, it is desirable to make use of well-known cell lines that have proven over the years to be useful for these purposes and to be free of complicating or contaminating factors (as described in the preceding quotations). Second, any cell line such as these must be approved by the Food and Drug Administration, which means that it is probably financially prohibitive to try to gain the same approval for other lines when these have already proven effective. This situation generates a difficulty for people who both oppose abortion in principle and would like to have the benefits of these vaccines. Opposing abortion “in principle” here means moral condemnation of elective abortion itself without regard to circumstances, motives, or beneficial consequences. The various reasons, theological or philosophical, that people might bring forward to support this opposition are not immediately relevant; it is necessary only that the opposition be principled. This kind of attention to moral good, i.e., moral good understood as decisively superior to goods of health and life, opens the door to a different order of opposition to vaccination. For using the vaccines produced in the manner described above appears to involve profiting from abortion and it is a question whether someone can both use these vaccines and oppose abortion without moral incoherence. Is the moral integrity of a person opposed to abortion compromised by benefitting from the research following the abortion, which research has led to the development of several powerful vaccines? Is it immorally opportunistic, vulture-like, or hypocritical for someone to take advantage of something he or she condemns as evil? Or, on the other hand, since the abortions have already been accomplished, is not the best course of action to pursue whatever good can be derived from these abortions? To answer these questions, it is necessary to try to determine the moral relationship of the use of these vaccines to the two abortions25 that have already taken place and to try to determine whether the use of these vaccines either condones or promotes further abortions."