Parent-offspring conflict concerns conflicts that arise over how much parental investment parents give to offspring. This occurs because the nature of the genetic relationships between parents and offspring means that they each have different priorities.

There are several explanations of sex differences in parental investment: that females typically invest more because they have already invested the most (Trivers, 1972); that females invest more because males have less parental certainty; or that females are less likely to have more offspring in the future (Gross and Sargent, 2005).

Human beings, in evolutionary terms, are vehicles for ensuring the continued existence of the genes they contain. They do this through sexual reproduction: the greater the number of offspring a human being produces the greater the probability that any genes it contains will continue to exist and the greater the probability that at least some of the offspring will go on to produce offspring of their own.