They might bring twice as much joy to their parents, but twins can also bring twice the expense and twice as much trouble as a single child.

According to a new study, twins do not double the odds of divorce. In fact, they only raise the risk slightly: parents of twins are only about one percent more likely to divorce than other parents.

The researchers who conducted the study say they're not sure why parents of twins have a slightly higher rate of divorce, but that the difference might be explained by the added financial and emotional burdens.

The study was conducted by a team led by Dr. Anupam Jena of Massachusetts General Hospital. They used information from the 1980 census, comparing marital statuses for those couples that had twins as their first-born and those that had single children.

Their sample turned out to exceed 800,000 families.

What they found was that of mothers who had a single child as their eldest, 13 percent were divorced and not living with the child's father. Of mothers who had twins as their first-born, the rate of divorce was 14 percent.

A doctor who studies parents of twins, but was not involved in this new study, told Reuters that stress and sleep deprivation can be worse for parents of twins, which might contribute to their higher rate of divorce.

She said parents of twins sometimes feel they spend so much time taking care of the needs of their infants that they don't have enough time to really enjoy the babies.

Of course, financial burdens are higher on parents of twins. It's estimated that the cost of raising a child to age 18 may now be as much as $250,000.

We should never forget that though expenses and stresses might be higher for parents of twins, there's also twice as much love and joy to go around.

Resource: Reuters: "Parents of twins slightly more likely to divorce": March 31, 2011