For the most part, religion per se has not been a major motivating force for genocide in modern times. However, religion has played a supporting role in some genocides.
For example, the Holocaust was not particularly a religiously motivated event. The victims were mostly Jews, but the motivation for killing them was not really religious. However, religion did help to create the setting for this genocide because it was religion that had led to a general attitude of anti-Semitism over the centuries.
There are times when religion is overtly used to promote genocide. The clearest recent case of this was in the Bosnian genocide of the 1990s. There, Christianity was explicitly invoked as a reason for killing Muslims.
Religion is a major motivating force for many people, helping to form their values. Religious beliefs are often very strong and compelling. This makes religion a "good" way to motivate people to participate in a genocide. However, it is not the only way and it would not be right to suggest that religion is necessarily connected to genocide.