The son of Mikhail O. Gershenzon. The scientist's fate reflected the pages from the history ofRussian genetics: its nascence, rise, persecution, and revival. In 1937, he was not allowed to be granted a Doctor of Sciences degree due to his belonging to the Morganist / Mendelist camp. During World War II, Gershenzon worked in the evacuation and, after his re- turn, he was accused of "cosmopolitism". After the notorious VASKhNIL session ni August 1948, the scientist was forced to renounce his scientific views and switch to another research area. During the Thaw, he took an active part in the struggle against Lysenkoism as well as in the exoneration of genetics and organization of molecular biology research in the Soviet Union. Sergei Gershenzon's innovative works- studies on the genetic role ofDNA and reverse transcription from RNA to DNA - garnered no support in his home country and, as a result, it was foreign scientists who were awarded a Nobel Prize for their works in this field. Even in the post-Perestroika period, the researcher encountered bureaucratic pressure and scheming on the part of his enemies when he struggled to register his scientific invention. In later life, Gershenzon was actively involved in science popularization, the struggle against cruel experiments and development of ethical principles of contemporary biology.