The theory therefore provides a new answer to the question: That is the surprising conclusion of zoologists who believe they have discovered the secret of one of society's most baffling mysteries: Their senior years display how strong are their genes. Such displays, in the elderly, are unconsciously reassuring to women. It is the very fact that an older male can still display his munificence that really makes a female's head turn. As a result, Proulx has put forward new findings in the Proceedings of the Royal Society - a theory that combines both the ideas of wealth and male longevity. In other words, in our evolutionary past, when people generally pegged it in their twenties, the fact that a man made it to his sixties indicated he must have something very powerful going for him genetically, a trend that still produces biological effects. Similarly, the reverse process - younger males seeking older females - occurs far more rarely because a woman's fertility starts to decline in her mid-thirties, and terminates in the menopause, researchers added. Proulx's theory is based on studies of the collared flycatcher and the three-spined stickleback. In other words, any stag that can still display a fine set of antlers in the twilight of its years, or an old peacock that can still rustle up a first-rate plumage - or an ageing Lothario who can still sport a Rolex and a riverside apartment - has to be considered a major catch. Only a creature with really powerful genes can do that and therefore attract females who are, in general, the ones who choose partners while males wait to be selected. It could be all over too quickly. Why not the other way round? However, the idea has been criticised because it does not explain why young women are not attracted to all older men. But he is far more likely to entice female mates than a younger man with a similar sports car.