Did the Tramp ever have an owner?
Based on the fact that he seems to know what (human) babies are, and his final words to Lady until after the baby is born are: "When the baby moves in, the dog moves out", I would suspect he may have. It's just that after his original owners had a baby, themselves, they kicked him out (either that or he ran away for being neglected). Otherwise, how would he know what human babies are?
Also, Jock and Trusty seem to know about babies, too (and are able to suspect Darling is pregnant, simply by what little details of hers and Jim Dear's "unusual" behavior Lady describes to them). As I questioned a while back on this board, who was was/were Jock and Trusty's owner(s) supposed to be? Did they ever have babies? And why did we never see either of those two dogs' owner(s)?
Either way, I'm beginning to think that the Tramp's former owners story may make an excellent fanfic or prequel, about the events leading up to how he met Lady. Sound interesting?