Morning sickness in men is much more common that the average person thinks. It's a symptom of Couvade syndrome, or sympathy pregnancy. Occurring across different cultures and socioeconomic classes, it can be the result of strong emotions regarding the pregnancy and the changing social roles of men.

One part of Couvade syndrome can be morning sickness in men. Also known as phantom pregnancy, the syndrome is a condition that results in an expectant father experiencing pregnancy symptoms as his mate does. These symptoms can include morning sickness, weight gain, altered hormone levels, sleep pattern disturbances, nosebleeds, postpartum depression and even labor pains.

Sympathy pregnancies in men are extremely common or very rare, depending on what symptoms you associate with the phenomenon. Using the common symptoms of Couvade syndrome as a reference, research suggests that sympathy pregnancies can occur in as much as 80 percent of expectant fathers. Rarer symptoms of Couvade syndrome, including belly growth and labor pains, might affect only 5 percent to 10 percent of fathers-to-be.

Morning sickness in men can begin as early as the first trimester and can last until the third trimester. It appears that symptoms are more common during the late stages of pregnancy and are likely to be more severe then, too. Expectant fathers should experience a total alleviation of symptoms after the birth of their child.

Sympathy pregnancy symptoms, such as morning sickness in men, can occur in any ethnic group or socioeconomic class. Men around the world experience the phenomenon, and it is not limited to any particular generation. Sympathy pregnancies are more likely to occur in men who have deep emotional attachments to the fetus or the mother. One study found that 92 percent of men with a deep emotional investment in the pregnancy suffered from sympathy pregnancy symptoms. It's been suggested that those who have had trouble conceiving with their mates might be more likely to experience Couvade syndrome symptoms such as morning sickness in men.

While many expectant fathers might suffer physically from sympathy pregnancies, the condition's legitimacy still is debated by experts. European research has questioned the condition's validity, but Western experts argue that the condition continues to grow among the male population. These experts believe that the increase in occurrences in the West is because of changing social roles. They contend that men in the West are more likely to experience sympathy pregnancies, including morning sickness, because Western men are encouraged to be more nurturing and active during pregnancies and as fathers.