Series creator Sherwood Schwartz collaborated with composer Frank DeVol to come up with the much-repeated theme song that describes what happens when a second marriage merges two families and six children under one roof. The song alone is memorable, but so is the opening sequence, which divided the screen into nine squares, one for each family member, including the housekeeper Alice. On the left, we saw the three daughters ". . . All of them had hair of gold, like their mother. The youngest one in curls." The right side introduced the three sons, who with their father made ". . . four men, living all together. Yet they were all alone." Who sang the song, you ask? The cast, of course!