While monogamy is generally accepted as the most appropriate form of relationship in most cultures, especially when it comes to having a child, new research reveals that women could improve the "quality" of their offspring by having multiple partners, the Daily Telegraph reports, via the American Academy of Pediatrics (AAP).
Experts from four different universities, including the University of Oxford, Stockholm University, University of East Anglia, and Linkoping University, analyzed an ancestor of the domestic chicken, the red junglefowl, and found that females who had various partners had chicks that were more resistant to disease. These findings could be applied to other animals, including humans, the researchers claim.
"Our research has shown that the females don't need to choose between males to produce the most healthy offspring," David S. Richardson of the University of East Anglia told the AAP. "Rather by mating with multiple males, they allow their internal choice mechanism to favor the most genetically different sperm. This could be the case in other animals - including humans, however the practicality of testing this in mammals would be very difficult, and obviously impossible in humans for ethical reasons."
In the new study, the researchers used both natural mating and artifical insemination of the red junglefowl, and wrote that the resulting effect of better quality offspring boils down to the "cryptic female choice," in which an internal mechanism in the female's reproduce tract favors the sperm of males most genetically different to them.
In addition, researchers found that a certain odor and variety of other signals given off by males helped the female birds choose the best quality mate on a subconscious level. In contrast, artificial insemination of the birds "lead to the genetic health of bred stocks being weaker," according to Richardon.
"Many breeding programs for livestock and conservation use artificial insemination. But our research suggests that this may not produce the best quality offspring," he said. "This is because the effect appears to require the subconscious female assessment of the male by some cue during actual mating. So having correct cues during mating, perhaps the smell of the male, can affect a females' chances of being fertilized. And the cues from different males may not work equally well on different females. This is something that needs to be explored further in various animals including humans."