The marbled electric ray exhibits aplacental viviparity, in which the developing embryos are nourished initially by yolk, which is later supplemented by nutrient-rich histotroph ("uterine milk") produced by the mother. Adult females have two functional ovaries and uteruses; the inner lining of the uterus bears a series of parallel lengthwise folds. The reproductive cycle for females is probably biennial, while males are capable of mating every year. Mating occurs from November to January, and the young are born the following year after a gestation period of 9–12 months. The litter size ranges from 3 to 32, increasing with the size of the female.