Researchers have found the key to a happy marriage. This secret ingredient could be a difference in height between the two partners. South Korea's professor Kitae Sohn said the taller the husband is, the happier the wife is. Mr Sohn said: "A greater height difference in a couple was positively related to the wife's happiness." He added that the attraction of a tall husband does not last forever. He said it disappears after 18 years or so of marriage.

Professor Sohn did not know why women preferred taller men. He said: "Although it has been known that women prefer tall men in mating for evolutionary reasons, no study has investigated whether a taller husband makes his wife happier." He wrote: "Women simply like tall men….This is similar to people favoring fatty, salty and sugary foods without knowing exactly why." However, the BBC said shorter men can be better husbands.