Another study also showed a higher divorce rate as the age difference rose for when either the woman was older or the man was older.
Within sexual selection Darwin identified a further two mechanisms which are important factors in the evolution of sex differences (sexual dimorphism): intrasexual selection (involve competition with those of the same sex over access to mates) and intersexual choice (discriminative choice of mating partners).
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.
There are also social theories for age differences in relationships as well as suggested reasons for 'alternative' age-hypogamous relationships.
Age-disparity relationships have been documented for most of recorded history and have been regarded with a wide range of attitudes dependent on sociocultural norms and legal systems. Relationships with age disparity of all kinds have been observed with both men and women as the older or younger partner.
It states that one should never date anyone under half their age plus seven years. Therefore, according to the above rule, this potential relationship is not so adequate.
Let’s take an example: The male protagonist in our story is 46. Of course there is a lot of controversy around this rule of thumb, especially nowadays, but it is said to have originated in France and set as a formula for suitability of a bride for marriage to an older man.
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".
A British psychological study published in Evolution and Human Behavior in 2010 concluded that men and women, in general, continued to follow traditional gender roles when searching for mates.
Dunn concluded that "Not once across all ages and countries ...
did females show a preference for males significantly younger than male preferences for females" and that there was a "consistent cross-cultural preference by women for at least same-age or significantly older men".
The result is: ■ The age difference between the two persons is 4 years, 4 months, 12 days.