 Participants undergoing an IVF treatment, are asked to respect an abstinence duration of 2-7 days. This is to obtain a sufficient number of motile sperm. A recent investigation, analyzed the quality number and motility of a sperm sample produced after an abstinence duration of 4 to 7 days, followed by a second sperm sample 2 hours later. The second sample after 2 hours was able to produce sperm cells with a higher motility. Not only has this short abstinence duration of 2 hours a positive effect on the motility, it will also reduce the sperm DNA damage, which again has a positive effect on embryo development. Because participants need gametes of high quality to obtain embryos with a high quality, the investigators want to investigate what the effect is of abstinence duration on embryo development. 