"One might object, however, that if we consent to the use of these vaccines, then we also consent to their origins in aborted fetal material. Such consent would represent a type of material cooperation with abortion. Yet another objection would be that use involves receiving a benefit from the immoral actions of others. What difference does it make, one might wonder, if the original immorality is now a part of the past? Most troubling, however, is the possibility that the present use of these vaccines might encourage future abortions. If that were true, then one might expect vaccination to constitute immoral cooperation with abortion."