Should you get married for tax purposes?

Though activist and model Jenny McCarthy has been together with actor Jim Carrey for five years, marriage has not seemed to be in the cards. In 2008, McCarthy announced on The Ellen DeGeneres Show that she did not intend to marry Carrey, saying the couple "didn't need a certificate."

That may be changing. McCarthy recently told Us Magazine that marriage is a possibility. "We say 'never,' but I don't know. Maybe for tax purposes, someday, when we are old."

But wait ... what about the so-called marriage penalty? Isn't getting married for tax reasons a bad idea? Isn't that what we've been told?

It depends on whom you ask. The Tax Code has flip-flopped over the years to make adjustments for a changing demographic and changing priorities. But no one "fix" has fit every situation.

Prior to World War II, the general rule was one income equaled one return. This made sense in traditional one income families where most women opted not to work. During World War II, the increasing numbers of women in the workplace (remember Rosie the Riveter?) resulted in the need for a change. In 1948, Congress adopted a joint tax return. Married couples combined their incomes and received deductions and exemptions worth roughly twice that of single filers. That structure stayed in place for more than 20 years until it was replaced in 1969.