From all the possibilities of assessment of the embryonic viability in vitro, morphology observed at microscope is the most elective criteria because of its specificity, sensibility and its armless side. The use of classifications at each stage of the development is essential for the selection of the right embryo to be replaced but do not allow dynamic evaluation. The development of computerized tools to capture and analyse images must emancipate us from oversimplification that doesn't cover frequent daily situations. The purpose is to examine the most frequent widespread classifications, the proposed alternatives and the consequences on embryonic replacement policy. More than a simple morphological factual evaluation of an attempt, it would be interesting to correlate embryonic development to stimulation criteria or quality culture media and other variables to enhance the obtaining of good prognostic embryos. The retrospective analysis of the databases of images will probably respond to this preoccupation.