The majority of insects lay eggs but a very few give birth to offspring that are miniature versions of the adult.[16] The aphid has a complex life cycle and during the summer months is able to multiply with great rapidity. Its reproduction is typically parthenogenetic and viviparous and females produce unfertilized eggs which they retain within their bodies.[25] The embryos develop within their mothers' ovarioles and the offspring are clones of their mothers. Female nymphs are born which grow rapidly and soon produce more female offspring themselves.[26] In some instances, the newborn nymphs already have developing embryos inside them.[16]