03/01/2009 05:12 am ET | Updated Nov 17, 2011

Not a Fish Tale: Female Promiscuity Leads to Better Sperm

Being a good girl doesn't help our species. Yes ladies, it turns out that in fish, if the female isn't promiscuous, the sperm and their offspring are impacted -- or to put it more delicately -- not impacted enough.

Now we all know the importance of the fast-swimming sperm and how it has an advantage when it comes to fertilizing an egg. But researchers decided to look at what motivated those sperm to want to be the first to the finish line. Wasn't it just predestined DNA and natural selection? Turns out it may be good ol' male competition. Nothing gets those fellas motivated than knowing there are other guys in the mix.

According to a study published in Proceedings of the National Academy of Sciences, (PNAS), a scientific journal, a research team demonstrated that unfaithful females of numerous fish species influence the males' sperm. Of course the term unfaithful isn't quite accurate. Let's just say that experience matters. And helps.

"The competition among sperms to fertilize a female's eggs is an extremely powerful evolutionary force that influences various characteristics of sperms, such as size and speed," says Niclas Kolm, a researcher at Uppsala University, who, in collaboration with scientists from several other universities, has studied the mating system of 29 species of Tanganyika cichlids. "For the first time, we can show a strong link between the degree of sperm competition and the size and speed of the sperms. Males with promiscuous females develop faster and larger sperms than the monogamous species."

Hmmm. Does this explain why Brad Pitt is now with Angelina Jolie vs. Jennifer Aniston? Is this why France's seductive First Lady Carla Bruni could easily entice her husband Nicolas Sarkozy? Girls with experience don't repel - as moralists would like to promote -- but instead may attract.

Furthermore, Sigal Balshine, associate professor in the department of Psychology, Neuroscience & Behaviour at McMaster University, and senior author on the study, also told Science Daily that promiscuous species create faster and larger sperm than those soley in monogamous relationships.

"This research offers some of the first evidence that sperm has evolved to become more competitive in response to females mating with multiple males," said Balshine, adding that female promiscuity is a major problem for males because sperm from rival suitors will "compete in order to procreate."

The appeal of Beyonce's "Single Ladies" also suggests that empowered women can get results. Until you get that ring gentlemen, it don't mean a thing.

As Science Daily observed, "while the notion that sperm would evolve to become more competitive when males compete for fertilization seems obvious, there has been little evidence to support this theory until now."

"[One] unique aspect of the study is that we based our study on an unusually large base, with many fish from many different species. The fish were caught in lakes in Africa, and a special characteristic of this group of fishes is that there are incredible numbers of species," Niclas says. "There's an unbelievable variety of species and different kinds of mating behaviors. There's the whole spectrum of mating systems, from monogamous males to females that mate with many many males."

He also added that,"No one has previously been able to show what causes what. Here we can clearly see that female promiscuity determines the character of sperms."

While we are grateful for Science Daily for reporting on this study, it does make us consider how this applies to the human species. Before, men had scientific excuses for why they may be promiscuous.

I once reported on the "lazy gene" that explained away moral lapses. Too hard to say no when presented with opportunity. Not making enough effort so the wife gets pissed off. However, now women have an excuse as well. We can say, like some do, that we improve by fishing around for a better catch.

Of course, being promiscuous isn't encouraged after you get married. In fact, this story supports what I know from counseling divorced couples and working at Your chances of long-term happiness and commitment exponentially increase if you experience more than one person to learn what you like and don't like. And having some experience with the opposite sex before marriage increases success. Which is why it is also said there are many fish in the ocean, and you don't need to settle on the first one until you swim around to find the right one for you.

This story was first published at