Mature reproductive cells are specialized cells that are capable of producing offspring. GAMETE, which is a 6-letter word, is a mature reproductive cell that is able to fuse with another GAMETE during fertilization. Sperm, which is a 5-letter word, is a type of GAMETE that is produced by males and is responsible for carrying the male's genetic material. EGG, which is a 3-letter word, is a type of GAMETE that is produced by females and is responsible for carrying the female's genetic material.