As many studies suggest an important negative effect of stress on well-being and sperm parameters in male infertility, we want to investigate the effect of expressive writing in male infertility.The expressive writing condition is compared to a non emotional writing condition, in which individuals write about mainly non emotional topics such as time management. In this randomized-controlled trial subjects were allocated sequentially by block wise randomization (block size of 4). For randomization a computer generated random list was used. The allocation was concealed in a series of numbered sealed envelopes. The envelope was opened immediately before the first writing session.