I don't see much parallel between Sturges and Mann. Sturges photographs in naturist communities (or at least did at one time) while both Sally Mann and Emmet Gowin did the early work for which they became known by photographing their family members. There was a strong connection to the subjects in Mann and Gowin's photographs that simply jumps out and grabs me. There is also a strong connection to place in those early photographs--specifically the American South.
The only thing Sturges had in common with the Mann and Gowin photos mentioned was that their subjects were often unclothed. Personally, I really haven't found much in Sturges' photography that moves me beyond admiration of the flesh.
Both Sally Mann and Emmet Gowin's more recent work has moved far beyond the photos depicted. Unfortunately, the last work I saw by Gowin was moving into digital. Sally Mann's work moved the other direction--wet plates.