False pregnancy False pregnancy False pregnancy, also known as phantom, hysterical pregnancy, pregnancy scares or pseudocyesis, is the appearance of clinical or subclinical signs and symptoms associated with pregnancy when the person is not actually pregnant. False pregnancy may sometimes be purely psychological. It is generally believed that false pregnancy is caused by changes in the endocrine system of the body, leading to the secretion of hormones that cause physical changes similar to those during pregnancy. Some men experience the same illnesses as a woman would experience while pregnant when their partner is pregnant (see Couvade syndrome), possibly caused by pheromones that
Male pregnancy sexual selection can be stronger on females than on males due to increased male parental investment. This reversal of traditional sex roles has only been found in pipefishes, whereas seahorses have largely been accepted as monogamous. Some pipefish species display classical polyandry because of this unique situation. Male syngnathids usually prefer females with large body size and prominent ornaments such as blue skin pigmentation or skin folds. Syngnathid males in some species are apparently capable of absorbing eggs or embryos while in the brood pouch. In these cases, embryos with the highest survival rate are those whose mothers display the