Board Thread:Theories Discussion/@comment-12515537-20151121035914/@comment-4188031-20151204005655

Yeah, I don' t think it could be Irregular; it's been well-established by now that anyone who is represented by the Kagamines is associated with Levia and Behemo some way, and so if he were the son of Maria Moonlit, that would leave the question of why he resembles the others. As for Adam, in QoTG, Levia and Behemo tell Maria to create vessels for them "the same way she created [her] son Adam", which to me seems to imply Adam is a ghoul child or otherwise artifically created.....though, I suppose that doesn't rule out the possibility of him having a father.