Yeah... the only evidence against this theory is that Sloane has always had a devotion to his wife Emily~ the only human part of his evil life. Would he screw it up? It's possible (like verdantheart suggested) that Irina is controlling Sloane w/ the fact that hey! do what I say or I'll tell Emily you have a daughter that's not hers...(even if Jack is syd's real dad.)
I agree, and why the hell would SYD be in jack's custody if sloane is her real father. It wouldn't make sense, i think that Jack is syd's dad. And why would he ever call her daughter? It's not like he really would say "daughter, come over here"??..
Yeah, Sydney really does need a paternity test, her and Jack are so different but are alike in other ways though. But hey, who knows, maybe they'll kill each other later on, wait No!!!! Don't kill Sydney!! I take that whole killing thing back