An overarching evolutionary theory which can provide an explanation for the above mechanisms and strategies adopted by individuals which leads to age disparity in relationships is called Life History theory, Life History theory posits that individuals have to divide energy and resources between activities (as energy and resources devoted to one task cannot be used for another task) and this is shaped by natural selection.
Parental Investment Theory refers to the value that is placed on a potential mate based on reproductive potential and reproductive investment.
There are also social theories for age differences in relationships as well as suggested reasons for 'alternative' age-hypogamous relationships.
These differences may be sexual, financial or social in nature. Socially, a society with a difference in wealth distribution between older and younger people may affect the dynamics of the relationship.
Although the "cougar" theme, in which older women date much younger men, is often portrayed in the media as a widespread and established facet of modern Western culture, at least one academic study has found the concept to be a "myth".
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.
In August 2010, Michael Dunn of the University of Wales Institute, Cardiff completed and released the results of a study on age disparity in dating.