A study released in 2003 by the United Kingdom's Office for National Statistics concluded that the proportion of women in England and Wales marrying younger men rose from 15% to 26% between 19.
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.
In females, relative youth and physical attractiveness (which males valued more compared to females) demonstrated cues for fertility and high reproductive capacity.
Buss stated the specific age preference of around 25 years implied that fertility was a stronger ultimate cause of mate preference than reproductive value as data suggested that fertility peaks in females around mid-twenties.
Male chimpanzees tend to prefer older females than younger and it is suggested that specific cues of female mate value are very different to humans.
Buss attributed the young age preference for females to the cues that youth has.
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".
In various cultures, older men and younger women often seek one another for sexual or marital relationships.Differences in age preferences for mates can stem from evolutionary mating strategies and age preferences in sexual partners may vary cross culturally.There are also social theories for age differences in relationships as well as suggested reasons for 'alternative' age-hypogamous relationships.The theory predicts that preferred mate choices have evolved to focus on reproductive potential and reproductive investment of members of the opposite sex.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.