Range of perspectives this 1st comment is interesting,
Especially with how the current economic situation is in America, I think it should almost be required. A lot of people's IRAs and 401Ks that they thought they'd live off of in their golden years have dwindled down to almost nothing. If you as their child have the ability to take care of them, you should do exactly that. Most parents would do anything for their children; you should if you have the ability, do the same thing for your parents.