I was listening to an interview about this recently, the theft of sperm from dead bodies was quite a common act in the middle ages and before, and some scholars theorize that the prevention of the act was one of the main reasons that prompted humanity to start burying or burning their dead. Of course, the interview didn't mention that it was Jews doing it, it was about accusations of demons, commonly succubi and incubi, performing the acts. But really, the more you look into it, you begin to realize that Judiaism is not merely the shitty religion of a shitty people, but actually something that is intensely demonic.