 The tradeoff for this cost depends entirely on whether the male is able to fertilize the other females’ eggs in the extra-pair copulation.For females, extra-pair copulations ensure egg fertilization, and provide enhanced genetic variety with compatible sperm that avoid expression of damaging recessive genes that come with inbreeding.Through extra-pair mating, females are able to maximize the genetic variability of their offspring, providing protection against environmental changes that may otherwise target more homozygous populations that inbreeding often produces.