Dr. Jan Tesarik obtained his MD degree in 1979 and PhD in 1982. From 1989 he worked at the Americaan Hospital of Paris and achieved the world’s first childbirths after round spermatid injection (ROSI) into oocyte cytoplasm. In 1998 he achieved, in Istanbul, the world’s first childbirth after oocyte fertilization with spermatids obtained by in vitro spermatogenesis. He developed an original technique for nuclear transfer in mature human oocytes (Rome, 2000) and achieved the first fertilizable human “artificial oocytes” reconstructed from somatic cell nuclei and donor ooplasts (Sao Paulo, 2001). He described beneficial effects of growth hormone on oocyte quality in women of >40 years old. He is author of >400 scientific publications, including 307 highly influential publications listed in Semantic Scholar. At present he is Director of MARGen (Molecular Asssisted Reproduction and Genetics) Clinic in Granada (Spain) and coordinates different research projects carried out at the University of Granada.