This show lasted 12 seasons and was a mainstay in my childhood homes. It took the family format (like "Leave it to Beaver" or "Father Knows Best") and turned it on its ear. There are no women in the Douglas household (though one of the men fills many of the traditionally female roles).
As the series progressed, characters were added or deleted---as with many shows---but "My Three Sons" (MTS) morphed so many times it felt like they were desperate to inject novelty. Eventually, they even brought women into the family.
Nevertheless, this was a popular series. A big part of that was due to the likable cast of characters. Even gruff Uncle Charley proved a softie whenever someone was down in the doldrums and needed attention. But the head of the household was the father, Steve (Fred MacMurray), the affable, cardigan-wearing, pipe-smoking gentleman who dispensed wisdom with a gentle tone and an earnest sincerity.
I think it is fair to measure a sitcom by its tendency to generate humor, drama or moments of tenderness. The MTS brand of humor is low-key, perhaps because the characters are laidback. As with most sitcoms, the drama is usually not dire. Most of the family's problems are not existential. But the all-male household does lend itself to occasional moments of tenderness, as when they decide to adopt Ernie.
This might not be one of the best shows of the sixties, but it provided comfortable viewing for many years.
