The possibility of crossing humans with other anthropoid species has been discussed in fiction as well as in scientific literature during the twentieth century. Professor Il'ya Ivanov's attempt to achieve this was critical for the beginning of organized primate research in the Soviet Union, and remains one of the most interesting and controversial experiments that was ever done on non-human primates. The possibility of removing the boundary that separates humans from other animal species, apes in particular, is loaded with important political meaning and violates cultural and ethical taboos. The history of Ivanov's scientific experiment thus helps to reveal some of the twentieth-century's important cultural conventions and hidden assumptions about human nature, species, and social hierarchy.