Study by Wooster Scientists Shows Promise for Enhancing Male Fertility

Student-faculty collaboration offers hope for couples trying to conceive

18 June, 2015 by John Finn

WOOSTER, Ohio — When couples have trouble conceiving, it's often the woman who endures the greatest scrutiny, but a new study by scientists at The College of Wooster suggests that male infertility might be consistently overlooked and that men can actually boost their sperm numbers.

Paul Joseph, a 2014 Wooster graduate, and Laura Sirot, an assistant professor of biology at Wooster, together with researchers at the Cleveland Clinic's Center for Reproductive Medicine, collaborated on the project, which considered the "Coolidge Effect," a phenomenon seen in mammalian species whereby the quality and quantity of a male's sperm would decrease with repeated exposure to images of the same woman but subsequently increase upon exposure to images of a new woman The research indicates that men, like males in other animal species, invest more (i.e. produce greater ejaculate volume with a greater number of motile sperm) when a little variety is introduced. Their findings are published in the June issue of Evolutionary Psychological Science.

Joseph and Sirot simulated mating scenarios with familiar and novel women using various images and then analyzed the different semen samples. "Our results revealed that when exposed to images of a novel woman, men ejaculated at a faster rate with higher volumes of semen that contained higher numbers of motile sperm," says Joseph. "This suggests that the men were able to differentiate between the two women they saw and produce larger ejaculates with more sperm for the depictions of a novel woman."

The findings also provide new insights for the fields of evolutionary biology and human evolutionary psychology, but the applications for male fertility medicine are particularly promising, say the two scientists. "Male infertility may be under-diagnosed since the ejaculates produced for analysis and for procreative purposes are generated under two different scenarios," says Joseph. "Ejaculates produced for procreative purposes are usually generated with a familiar woman, while those that are analyzed in a clinical setting are usually generated while viewing images depicting a novel woman. Thus, the ejaculates produced in fertility clinics may be of higher quality than usual, which may conceal any potential fertility problems experienced in the bedroom."

Joseph and Sirot hope that the results will provide insight into ways to improve the diagnosis and treatment of fertility problems, thus boosting chances for conception, while sparing women invasive diagnostic and treatment procedures.