If you are basing this question on the movie Inferno, then you have this phrased totally wrong. The question should be if it is better to combat overpopulation by releasing a virus that causes a part of the human population to be infertile so that they can't physically have children.
@Fettywapapa What I was asking was is it worse for the planet to be overpopulated or to combat overpopulation through a plague as Zobrist attempted to do in the film. Between those two, which is the greater evil? That's what I meant. In the novel, it was a sterilization virus, and in the film they changed it to a plague. Between those two, sterilization sounds more humane.