Opposites Attract

No, it's not Paula Abdul's song. According to neuroscientist Simon LeVay “Some degree of difference between same-sex partners is probably necessary for the establishment and maintenance of loving sexual relationships. With a man and a woman, this essential difference is supplied automatically by the very fact that the union crosses the sex divide. Differences between that, in age, race and so forth, may tend to overload a couple’s capacity for mutual understanding, or may provoke social intolerance, which would explain why most stable heterosexual partnerships are between fairly similar people.” SOURCE