[Which assisted reproduction technique as a function of sperm morphology?]

Semen analysis is routinely part of the evaluation of male fertility and includes sperm morphology. How sperm morphology can be a diagnostic tool to decide which ART to apply for infertile couples (insemination, classical IVF or ICSI)? Teratozoospermia has been reported to be one of the most relevant semen parameters of clinical interest compared with sperm concentration and sperm motility. However, the true potential of this parameter has some limitations because of several methodological factors: differences in the classification systems, influence of the staining method used, subjective nature of evaluation of sperm morphology, regular decreasing of the WHO threshold. According to Tygerberg strict criteria that is the most frequently used classification worldwide, poor fertilization has been reported when the rate of normal forms was less or equal to 4%, suggesting to perform ICSI. However, influence of sperm morphology on fertilization outcome remains much debated. Regarding David's classification, the threshold of 30% does seem helpful to discriminate in the prediction of fertilization success and should probably be reconsidered.