Why do many hermaphroditic animals use cross-fertilization?

Many hermaphroditic animals utilize cross-fertilization because it facilitates the recombination of genetic material from two different parents. By mixing hereditary traits, cross-fertilization increases genetic variability within a population, which provides a broader range of traits for natural selection to act upon.123

This increased genetic diversity is crucial for a species' ability to adapt to environmental changes, whereas self-fertilization—while sometimes possible—often limits this adaptive capacity and can lead to an evolutionary "cul-de-sac". Even though hermaphroditic animals possess both male and female reproductive organs, many have evolved specialized mechanisms to avoid self-fertilization and ensure that cross-fertilization occurs. For example, many hermaphroditic species engage in mutual copulation, where each individual in a mating pair introduces sperm into the body of the other.1432