A fertility-enhancing cooling seat for lowering temperatures of human testicles so as to increase sperm quality and quantity. The cooling seat includes: a top flexible portion and a base portion; a bottom flexible portion coupled to the top flexible portion, the bottom flexible portion forming a seal with the base portion, portions of the bottom flexible portion and portions of the top flexible portion defining isolated cooling cells with cooling-cell volumetric spaces; a phase-change material located in the cooling-cell volumetric spaces, the phase-change material configured to change from a solid phase to a liquid phase at a first temperature and that is configured to change from a liquid phase to a solid phase at a second temperature that is lower than the first temperature. At least one of the isolated cooling cells defines a diameter that is larger than a diameter of the other of the cooling cells.