Qualifying Child of Another Taxpayer
Todd has lived all year with his girlfriend, Eva, and her two children in his home. This cohabitation does not violate local laws. Eva is not required to file, and does not file, a 2011 tax return. Eva and her two children pass the "not a qualifying child test" to be Todd's qualifying relatives. Todd can claim them as dependents if he meets all the other tests.
What if all the facts were the same in this example, except that Eva is required to file a tax return, since she earned $12,000?
Since Eva has a filing requirement and her children meet the qualifying child tests to be her dependents, Todd can no longer claim the children as qualifying relatives.