There
are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying
Relative" in IRS parlance even though they don't have to actually be
related). There is no income limit for a QC but there is an age limit, a relationship test and a residence test. Only a QC
qualifies the taxpayer for the Earned Income Credit, the Child Tax Credit. So, the child may qualify as a
dependent, but because she is not related, she cannot be your qualifying child for
the earned income credit, child tax credit or Head of Household (HoH) filing status.
Your biological child will qualify you for HoH.
