 Vonnegut mentions overpopulation not only in "Welcome to the Monkey House" but also in another story from the same collection, "The Big Trip Up Yonder/Tomorrow and Tomorrow and Tomorrow" (1954), in which he describes how in the Year 2158, six generations of a family live together in just one small apartment.Some of these ideas are also present in Vonnegut's story 2 B R 0 2 B.He wants to draw his readers’ attention to the threat of overpopulation in order to avoid the scenarios that are described in his stories.