accelerated timeline and to support induced lactation in menopausal parents. Some couples may stimulate lactation outside of pregnancy for sexual purposes. Rare accounts of male lactation (as distinct from galactorrhea) exist in historical medical and anthropological literature, although the phenomenon has not been confirmed by more recent literature. Domperidone is a drug that can induce lactation. Evolution Charles Darwin recognized that mammary glands seemed to have developed specifically from cutaneous glands, and hypothesized that they evolved from glands in brood pouches of fish, where they would provide nourishment for eggs. The latter aspect of his hypothesis has not been confirmed; however, more recently the same mechanism has been postulated for early synapsids. As all mammals lactate, lactation must have evolved before the last common ancestor of all mammals, which places it at a minimum in the Middle or Late Triassic when monotremes diverged from therians. O. T. Oftedal has argued that therapsids evolved a proto-lacteal fluid in order to keep eggs moist, an adaption necessitated due to synapsids’ parchment shelled eggs which are more vulnerable to evaporation and dehydration than the mineralized eggs produced by some sauropsids. This protolacteal fluid became a complex, nutrient-rich milk which then allowed a decline in egg size by reducing the dependence on a large yolk in the egg.[20] The evolution of lactation is also believed to have resulted in the more complex dentition seen in mammals, as lactation would have allowed the prolonged development of the jaw before the eruption of teeth. During early evolution of lactation, the secretion of milk was through pilosebaceous glands on mammary patches, analogous to the areola, and hairs on this patch transported the nourishing fluids to the hatchlings as is seen in monotremes. The development of the nipple occurred in the mammal lineages that diverged after monotremes, metatheria and eutheria. Occurrence outside Mammalia Another well known example of nourishing young with secretions of glands is the crop milk of columbiform birds. As in mammals, this also appears to be directed by prolactin. Other birds such as flamingos and penguins utilize similar feeding techniques. The discus fish (Symphysodon) is known for (biparentally) feeding their offspring by epidermal mucus secretion. A closer examination reveals that, as in mammals and birds, the secretion of this nourishing fluid may be controlled by prolactin. Similar behavior is seen in at least 30 species of cichlids. Lactation is also the hallmark of adenotrophic viviparity