The sexy son hypothesis is a concept from evolutionary biology, proposed by P. J. Weatherhead and R. J. Robertson in 1979. It posits that a female animal's optimal choice among potential fathers is a male whose genes will produce male offspring with the best chance of reproductive success. In particular, the sexy son hypothesis implies that a potential mate's capacity as a caregiver or any other direct benefits the male can offer the female (eg. nuptial gifts, good territory) are irrelevant to his value as potential father of the female's offspring.
The sexy son hypothesis has been suggested as the origin of some aspects of human sexual behavior. In particular, it has been shown that human females are more attracted to traditionally masculine men ("cads") during the most fertile times of their menstrual cycles, and more attracted to relatively feminine men ("dads") during the remainder of the cycle. These observations have led to the conclusion that infidelity is a natural occurrence in women, and evolutionarily advantageous, on the grounds that it will enable them to secure both the best genes and the best caregiver for their offspring.
This article is based on "Sexy son hypothesis" from the free encyclopedia Wikipedia (http://en.wikipedia.org). It is licensed under the terms of the GNU Free Documentation Licencse. In the Wikipedia you can find a list of the authors by visiting the following address: http://en.wikipedia.org/w/index.php?title=Sexy+son+hypothesis&action=history