Now that we can clone humans they've removed the one pleasurable thing about having a child.

The line is a characteristically deadpan, risqué joke that treats a serious scientific development—human cloning—as fodder for late-night satire. Letterman’s humor hinges on misdirection: instead of debating ethics, identity, or medical promise, he reduces “having a child” to the sexual act of conception, implying that cloning would bypass it. The punchline also plays on cultural anxieties that technology can sterilize or mechanize intimate human experiences, turning reproduction into a clinical procedure. As with much monologue comedy, the exaggeration is the point: it mocks both sensational media coverage of cloning and the tendency to frame complex issues in simplistic, self-interested terms.