Dr Jacky Boivin, from the School of Psychology at Cardiff University, studied 71 women with an average age of 30.
BBC: Passionate sex aids pregnancy
2.
The lead researcher from Cardiff University, Professor Jacky Boivin, said that it was a "common myth" that women who were stressed would impede the effectiveness of fertility treatment.
BBC: Fertility treatment success is not prevented by stress
3.
Dr Boivin found that almost half the women who experienced disappointing sex retained no sperm at all, compared with only one in ten women who had enjoyed a satisfying sexual encounter.