How about 1920s? It's not clear how far it went. > "Ilya Ivanovich Ivanov was the first person to attempt to create a human–chimp hybrid by artificial insemin

How about 1920s? It's not clear how far it went. > "Ilya Ivanovich Ivanov was the first person to attempt to create a human–chimp hybrid by artificial insemination." https://en.wikipedia.org/wiki/Humanzee https://en.wikipedia.org/wiki/Humanzee