They weren't (thank god… At least that). Val grew up sheltered in an attic and being cared for by an old woman (who he doesn't even know if she's related to him. He has no memories of who his parents are since he was taken to the attic before he could start forming his first memories). The people who tortured him are strangers he ran into after breaking the one rule and venturing outside, they just thought of him as some sort of monster and you know the rest.

I don't think his mutation is the result of inbreeding, I think it's a simple case of mutagens or DNA replication error. Hence why Coeus is curious to know if it's a germline mutations (that occur in eggs and sperm) and can be passed on or a somatic mutations (that occur in body cells) that cannot. You know, so he can have another of him in case something happens-

But huh. Guess he'd have to give him the talk before he can ask him to jerk off in a cup. Or maybe it's better he doesn't explain to him why he wants that sample.