Well, Adam Sandler won't father a Brad Pitt. But it seems that only Brad Pitt can father another Brad Pitt...This happens in the insect world as well.

Attractive traits have been known to be passed on from parents to offspring, from cricket calls to peacocks' tails, but being really sexy is more complicated. Anyhow, a team at the University of Exeter, in a study published in Current Biology and made on the fruitfly Drosophila simulans, reveal that male attractiveness is really a question of genes.

Male and female flies were paired at random and the time till mating took place varied from only two minutes to two hours. As female fruitflies have high control of their genitalia, males cannot force copulation. Thus, the time it took the male to penetrate was a sign of his sexual attractiveness.

Each male copulated 3 females, their sons being full (33 %) and half (66 %) brothers. The researchers measured again how much time the sons needed to have sex with a female. It appeared that this period of time coincided with how much time it took to their own father to conceive them.

Researches have revealed that females mating with attractive males did not lay more eggs than in the case of mating with less attractive males. Now it seems that having attractive sons fathered by sexy fathers will mean more descendants in females' genealogy, as they mate easier and with more females.

"Attractiveness probably can't be defined by individual characteristics, so there is no single physical attribute that female fruitflies are looking for in a mate. However, there is clearly a benefit to females in having sexy sons that are more likely to attract a mate and produce offspring." said Dr David Hosken of the University of Exeter.

Researchers wonder if this is also valid in the case of more species.

"It's possible that attractiveness is hereditable across the animal kingdom. It could even be the case in humans that the sexiest dads also have the most desirable sons, which would probably be bad news for my boy." said Hosken.