Cockroaches practice sexual reproduction. While the reproduction process can vary slightly from species to species, in most cases the female roach releases pheromones to attract a mate. The male roach then deposits his sperm into the female.
Most roaches are oviparous, which means the mother carries the fertilized eggs in a sac, called an ootheca, outside of her body while they grow and develop. The ootheca attaches to her abdomen and must stay moist during gestation in order for the eggs to hatch. A few roaches are ovoviviparous, which means the young grow and develop in an ootheca located inside the mother's body. These roaches give birth to live nymphs.