The project is a RCT follow the orientation of CONSORT. The investigators propose to assess one method of sperm selection based on the characteristics of spermatozoa recently introduced: Sperm Selection Assay, which used a gradient of concentration of progesterone to act as chemoatractant of spermatozoa of better quality. We will assess in vitro fertilization with two techniques (SSSA versus traditional technique of swin up) as well as embryo development.