Imagine you have two candidates for a job. Their CVs are equally good, and they both give good interview. You cannot help noticing, though, that one is pug-ugly and the other is handsome. Are you swayed by their appearance? If you were swayed by someone's looks, would that be wrong? In the past, people often equated beauty with virtue and ugliness with vice. Even now, the expression 'as ugly as sin' has not quite passed from the language. There is, of course, the equally famous expression 'beauty is in the eye of the beholder', to counter it. Most beholders agree what is beautiful — and modern biology suggests there is a good reason for that agreement. Biology also suggests that beauty may, indeed, be a good rule of thumb for assessing someone of either sex. Not an infallible one, and certainly no substitute for an in-depth investigation. But, nevertheless, an instinctive one, and one that is bound to contribute to the advantage of the physically well endowed.