Males masturbating to women they have seen before produce higher quality semen, research has found in the United States. The College of Wooster, Ohio conducted the study using 21 heterosexual males and some pornography material concluding that when men encounter ‘novel women’ they tend to ejaculate faster, while their semen is of better quality and more in volume. However, Dr. Laura Sirot, one of the co-authors of the study made it clear that the findings did not suggest in any way whether monogamy was favoured or disfavoured by natural selection. In other words, this does not mean males are somehow programmes to cheat on their girlfriends through natural selection. The study provides new insights into evolutionary biology, but could also lead to an improvement of detecting and treating male fertility problems.