That was Ernie.... he was adopted - so he doesn't count. No...no...Ernie was actually the 4th son. Mike, Robbie & Chip were the original three sons. Mike (Tim Considine) got PO'ed and didn't renew his contract & was written out of the show. Well, M3S's wouldn't work with only TWO sons, so enter Chip's (Stanley Livingston) real-life brother (Barry Livingston) as Ernie. Ernie was Chip's friend, and an orphan who was facing going back to the orphanage after his foster parents were going to move out of the country. Steve Douglas to the rescue!!! He adopted Ernie - and M3S's could remain M3S's instead of having to change the opening footage to two feet tapping to the music and changing the name to M2S's.