Head of Household

Not unless the person in question is a foster child placed with you by an agency. See IRS Publication 501.

I don't think it is limited only to a foster child. Stepchild, stepbrother or stepsister (or descendant) also seem to qualify.

Pub 501 says "The term ³qualifying child² is defined under Exemptions for Dependents", which says " The child must be your son, daughter, stepchild, foster child, brother, sister, half brother, half sister, stepbrother, stepsister, or a descendant of any of them."

I guess things are different where I grew up. All those were considered "related " to me.

I didn't know if the OP would consider those to be related, some people don't. A lot of people go through adoption procedures to adopt a stepchild because they don't feel related until they do. Many people also think that related by blood and related by marriage are different.

Interestingly, the "step-" relationship created by marriage doesn't end for tax purposes even if the marriage does.

-Mark Bole