Experimental embryology achievements in previous century resulted in the birth of the first child conceived artificially. Besides its obvious social significance, the successful solution of the “test-tube babies”, provided also the unique chance for direct inspection of human embryos growing in vitro at their earlier stages. New technologies applied for human gametes and earlier embryos studies, combined with high resolution capacities of modern cytogenetic and molecular methods helped a lot in elaboration of efficient algorithms for ARTs and also provided solid background for illumination of many genetic problems of human development before impantation. The later include: input of chromosome aberrations and genome imprinting in pathology of early human development, cytogenetic and molecular mechanisms of the primary embryonic differentiation, genome epigenetic changes since fertilization trough cleavage and blastulation, identification of genes responsible for early development and differentiation. Conspicuo