"When aborted fetal tissue is transplanted into others for experimental or therapeutic purposes, the very use of the tissue uses it up and additional uses require an additional supply of tissue, normally made available by further abortions. In vaccine production, the currently available cell lines provide all the fetal material that is needed now and, apparently, in the future. Indeed, the success of these particular cell lines makes it unlikely that any new lines will be developed (whether from induced or spontaneously aborted children). Hence, the production techniques themselves do not require further abortions. The moral difference between vaccine technology and tissue transplantation is not changed by the fact that the product labeling for Varivax, for example, states that each dose contains “residual components of MRC-5 cells including DNA and protein.” These trace particles do not function in any sense as active components in the effectiveness of the vaccine. Still, it remains necessary to inquire into the relationship between the production of the vaccines and the two abortions that yielded the tissue. According to all available reports, in both cases the decision to abort was independent of the desire to make use of fetal tissue. In other words, the abortions would have taken place whether or not the cell-line research would have followed. This means that the abortions were not undertaken in order to produce vaccines or to fulfill any other research purpose. Moreover, nothing indicates that the vaccine production requires cell lines from electively aborted fetuses; tissue that is sufficiently healthy to produce cell lines of the type requisite for vaccine production might have become available from a fetus that died from some other cause. Granted, healthy tissue is more commonly found in electively aborted fetuses, but nothing indicates that such tissue is necessarily unavailable from other sources. These points suggest that vaccine production and, hence, use is morally separable from abortion, even though current production in fact depends upon cell lines derived from aborted fetal tissue. Vaccine production and abortion are morally independent, which is to say that vaccine use and opposition to abortion are in principle morally coherent."