Board Thread:General Discussion/@comment-3271485-20150320233013/@comment-26217701-20150409141625

Yugioh z wrote: Okay Crazy theory time: Rose had discovered a way to fuse with Humans. She and Greg then attempted a fusion that succeeded. Greg and Rose succeeded in fusing and Greg witnessed some of her memories. These memories freaked him out and forced them to defuse. Defusing resulted in Rose becoming pregnant with Steven.

That is extremely unlikely.