i too have asked this question and didn't get an answer. i was with a guy for 11 years that wasn't my kids' father. he claimed head of household and my two children. we never got audited or questioned about it. 12 yrs later, me and my 7 yr old son have been living with my new boyfriend for almost 3 yrs. i do not work. he supports us 100%. we seem to meet all the requirements for claiming a dependent, but i'm still confused about the relationship aspect of the requirements. i just wonder if we are not married, does my son fall under the stepchild category. my boyfriend didn't claim head of household the last two yrs because he thought that if my son wasn't his blood relative, that he couldn't claim him and hoh. i have seen several Q&A's that had similar questions, and the answers were always yes, you can claim hoh and your gf's or bf's children. soooo.. hopefully we can get this cleared up asap.. i don't know who else to ask!