Flat buttocks are most often of congenital origin, related to the morphology of the person. They can also result from significant weight loss.
This defect affects both sexes but it is more unsightly in a woman than in a man, mainly for cultural reasons. A woman with a well rounded buttocks is considered more feminine and more attractive. There is also an injustice related to birth. A man, if he is well muscled, will achieve an acceptable rounded shape, while a woman, even if muscled, will have a well toned but still flat buttock. It will therefore be necessary to make a bulge above to give volume.
Most often, a liposuction of the hips is associated with a gluteal implant in order to better emphasize the curve obtained.