If you look like Pete Doherty, you can not be 100 % sure that you fathered your children.
That's because a new research shows that a woman prefers a stud when she is fertile and just wanting to play rather than a mate for life.
The new approach shows how the price a women puts on the masculinity of her mate shifts during her reproductive cycle and with her immediate and long-term goals. This preference for hunker men was also closely connected to the woman's self-esteem and how attractive she regarded herself.
The patterns of the woman's sex drive seemed to be largely out of her control. Previous investigations have already revealed that women regard partners with high facial masculinity-square jaws and well-defined brow ridges-as proper for affairs, while more feminine features were considered as indicators for long-term mates.
Another investigation pointed to the fact that men find women as better smelling at certain points in their menstrual cycles.
The new research correlated how women regard their own attractiveness with different moments of their menstrual cycle. They were presented image pairs depicting "feminized" and "masculinized" variants of the same male body and asked to choose the body type for short-term and long-term relationships, at opposite points in their cycle. "Fertile women chose the masculine version of each image 15 % more often, on average, than women who were not fertile," said lead researcher Anthony Little, a psychologist at the University of Stirling in Scotland.
The effect was correlated with how attractive the women considered themselves. The researchers speculated this on the testosterone levels of the males. This hormone is not good by itself: it can depress the immune system, and eunuchs, who have low levels of it, live longer than normal males; however, it signals good quality. "Only males in good condition can bear high testosterone levels, because they require a great deal of energy and can only be sustained in healthy individuals," said UCLA researcher Dave Frederick, who was not involved in the study.
Therefore, macho men have better genes for producing better babies, that's why fertile women will seek them to father their children. But women prefer more feminine body types when they are not fertile, because high levels of testosterone make men more promiscuous. That's why lousy males tend to invest more in relationships and they are more attractive for women who need a mate to invest in their offspring.
But women who perceive themselves less attractive are less likely to score a high-quality mate, as their brains may impede them from wanting what they can't have, like an insurance "they're partnering up with someone who's most likely to reciprocate their own interest," said Little.
That's why everybody has his/her partner on the face of the earth. "Brad Pitt might be the most attractive man in the world, but he's not everybody's cup of tea," he said.