Men who view pornographic images of two men and a woman produce better-quality sperm than men viewing pornographic images of just women, an Australian study reveals.The finding suggests that humans may be capable of subconsciously increasing semen quality when faced with the possibility that their sperm will have to outrun those of other men in a woman’s reproductive tract.In the study, zoologists Leigh Simmons and Sarah Kilgallon of the University of Western Australia in Perth asked 52 heterosexual men aged between 18 and 35 years to ejaculate into a container after viewing the two types of image. The volunteers had previously abstained from sexual activity for two to six days. In samples from men who viewed the images containing the two men and a woman - the “sperm-competition” images - 52% of the sperm were motile. This compared with 49% sperm motility in the men who viewed the images of women only – a difference that was statistically significant after taking into account lifestyle factors such as cigarette smoking and alcohol consumption.But there was also a seemingly contradictory finding. Men who viewed the sperm-competition images had fewer sperm in their ejaculate: 61 million per millilitre compared to 77 million per millilitre for the men who viewed the female-only images. More studies are needed to explain this finding.
