Im telling u the only reason Sanji hasn't been taken over by his germa genes is due to CoC
Being able to turn it on and off keeps it under control, he asked Zoro to stop him and even kill him because he legitimately felt it could be needed.
It makes no sense that he can turn it "ON/OFF" if he was born with it and its his siblings blood, there is something else.
Even Reiju can't do this, and she was raised mostly by Sora.