OK. This is completely nuts. From weirduniverse.net:
The Human-Ape Hybrid
For decades dark rumors circulated alleging that the Soviets had conducted experiments to try to create a human-ape hybrid by breeding chimpanzees and humans, but it wasn't until the collapse of the Soviet Union and the opening of Russian archives that the rumors were confirmed.
Dr. Il'ya Ivanov was a world-renowned expert on veterinary reproductive biology, but he wanted to do more in life than breed fatter cows. So in 1927 he traveled to Africa to pursue his vision of interbreeding man and ape.
Thankfully his efforts weren't successful. This was due both to genetics, and to the native staff of the West Guinea research facility where he worked, from whom he constantly had to conceal the true purpose of his experiments. If they had found out what he was really doing, he wrote in his diary, "this could have led to very unpleasant consequences." The necessity of carrying out his work in secrecy made it almost impossible to do anything, although he did record two unsuccessful attempts to artificially inseminate female chimpanzees with human sperm.
Frustrated, Ivanov eventually returned to the Soviet Union. He brought an orangutan named Tarzan back with him, hoping to continue his research in a more accepting environment. Back home he advertised for female volunteers willing to carry Tarzan's child, and remarkably he got a few takers. But then Tarzan died and Ivanov himself, suspected of harboring counter-revolutionary sentiments, was sent off to a prison camp for a couple of years. This ended his research. There are vague rumors suggesting that other Soviet scientists continued Ivanov's work, but nothing has been proven.