Nested graduated toilet seats

A toilet seat assembly, comprising:

• three or more toilet seats of sizes downwardly graduated from relatively smaller toilet seats to relatively larger toilet seats, from a smallest top toilet seat to a largest bottom toilet seat;
• a toilet seat lid, which is configured to fit over and cover the toilet seats;
• wherein the toilet seats and the toilet seat lid are connected to a common cooperative hinge member, which is configured so that each of the toilet seats and the toilet seat lid can be independently raised and lowered;
• wherein each of the toilet seats has a substantially annular or oval annular shape, which defines a central, substantially circular or oval seat opening, and wherein the seat openings are downwardly graduated from a smallest top seat opening to a largest bottom seat opening;
• wherein each of the toilet seats comprises the seat opening, a downward seat flange surrounding the seat opening, a declining inner seat contour surrounding and transitioning into the downward seat flange, a middle seat contour surrounding and transitioning into the declining inner seat contour, and an outer seat contour surrounding and transitioning into the middle seat contour;
• wherein each of the relatively smaller toilet seats, when lowered, nests within the declining inner seat contour of the relatively larger toilet seat below it, and the downward seat flange of the relatively smaller toilet seat engages an entire inner perimeter of the downward seat flange of the relatively larger toilet seat below it, so as to define the seat opening of the relatively smaller toilet seat;
• and
• wherein the largest bottom seat, when lowered, rests on a toilet bowl rim, and the downward seat flange of the largest bottom seat engages an inner perimeter of the toilet bowl rim, so as to define the largest bottom seat opening.