Men ejaculate high quality of sperm when they do sex with new partner than familiar ones, according to a study.

The researchers from The College of Wooster in Ohio, USA asked 21 men to provide semen samples while watching seven different explicit three-minute clips of a male and female having sex. The participants used the same private room to produce the semen with 48 to 72-hour breaks between each session.  The first six clips used the same male and female actor while the seventh clip used the same male actor but involved a different female. They recorded the quality of sperm and the length of time it took ejaculate. Finally the researchers noticed that the men produced healthier, higher volume of sperm, when they were exposed to seventh clip featuring a different female.

“An increase in the total number of motile sperm may result in higher likelihood of fertilisation and greater ability to compete with other male’s sperm,” Whereas a decrease in the time to ejaculation may decrease the likelihood of an extra-pair copulation (with a partner that is not your own) being detected.

The study was published in the Journal of Evolutionary Psychological Science and hopes that the findings can be used to aid the treatment of infertility.

By Lizitha