These two theories explain why natural and sexual selection acts slightly differently on the two sexes so that they display different preferences.For example, different age preferences may be a result of sex differences in mate values assigned to the opposite sex at those ages.These age preferences were confirmed in marriage records with males marrying females younger than them and vice versa.This study used 21,245 participants between 18 and 65 years of age who were not involved in a close relationship.
This theory predicts both intrasexual selection and intersexual choice due to differences in parental investment; typically there is competition among members of the lower investing sex (generally males) over the parental investment of the higher investing sex (generally females) who will be more selective in their mate choice.
Age disparity in sexual relationships is the difference in ages of individuals in sexual relationships.
Concepts of these relationships, including what defines an age disparity, have developed over time and vary among societies.
The rational choice model suggests that people look for partners who can provide for them in their life (bread-winners); as men traditionally earn more as they get older, women will therefore prefer older men.
One of the concerns of relationships with age disparities in some cultures is a perceived difference between people of different age ranges.