People's predilections for promiscuity lie partially in their DNA

A particular version of a dopamine receptor gene called DRD4 is linked to people's tendency toward both infidelity and uncommitted one-night stands. The same gene has already been linked to alcoholism and gambling addiction, as well as less destructive thrills like a love of horror films. One study linked the gene to an openness to new social situations, which in turn correlated with political liberalism.