Long story short. Found out I had a half brother and he's been staying with me for the past year while going to a nearby community College.

Was doing my taxes and discovered he technically qualifies as an dependent and I can claim head of household status.

However, he has a different last name and is only genetically related but not in a legal sense (i.e. birth certificate doesn't have father's name).

Can I still claim him as a dependent? Will IRS call or ask for additional proof? I can provide evidence in genetic tests but I'm guessing I'm over thinking this unless I'm audited.

  • The interesting question is whether the IRS would accept just the evidence of genetic tests. I can see that there could be many situations of the "your father's not your father" sort.
    – jamesqf
    May 7, 2020 at 16:44
  • Did he get a stimulus check? There was something about adult dependents not qualifying for it or something...
    – Nat
    May 7, 2020 at 20:27
  • @Nat Not yet but he's on the list. He hasn't filed for 2019 and is waiting for me to get back to him
    – deek
    May 7, 2020 at 21:32
  • 2
    @deek: I'm fuzzy on all of these rules, I've just heard that adult-dependents don't qualify for the stimulus check (which is like $1200, I think?) while them being declared as a dependent tends to get a lesser tax credit than that. So while stressing that I'm not clear on these rules, I'd be hesitant to claim someone as a dependent if doing so would be optional. (Plus it's not impossible that there may be another round of stimulus checks later, such that declaring someone was a dependent may cost further stimulus checks in the future.)
    – Nat
    May 7, 2020 at 21:35
  • Suppose that Question goes unresolved for two or three - or 20 or 30 - years… At that point, how likely is the IRS to give you the benefit of any doubt? That being almost certain, why not now ask IRS for analysis of a theoretical case? May 8, 2020 at 20:51

3 Answers 3


This appears to be something that is done on the honor system. The biggest check the IRS does is with the social security number. They will make sure that nobody else is claiming your half-brother.

So before you do this you need check a few things:

  • Nobody else is claiming him. It is possible that either parent might also believe they can claim them. If multiple people claim the same person, then the IRS will investigate. It is also possible that if the other people have already filed their forms, then your entire return may be held up while it gets sorted out.
  • Education credits. Make sure that your claiming him doesn't impact how education credits are being allocated.
  • Which leads to the FAFSA. In Some situations the parents income, savings, and debts play a role in the determination of how much aid is available. In other cases it is the only the students situation. By claiming the student on your tax form it is likely that your income, savings, and debts will be added to the mix.
  • 5
    One your first point, that includes the half-brother. One of the questions on the 1040 form is whether someone else can claim you as a dependent. If the half-brother files himself, he will need to check the box that says someone is claiming him as a dependent. That will affect his standard deduction.
    – Seth R
    May 7, 2020 at 17:22
  • 2
    I would go even further. Last time I checked, they don't actually care if someone is genetically or legally related to you - only that they're a member of your household (i.e. staying with you) and dependent on you (and that any taxes filed by anyone agree on this.) Pretty sure I could've claimed my roommate as a dependent the year they didn't pay rent, had their parents not already done so. May 8, 2020 at 15:05

As with most things on your tax return, you are on the honor system until you are audited. If you claim him as a dependent, it will most likely be accepted and no proof will be asked for.

If you are audited, you have evidence.


First, you need the brother's SSN. People don't give their SSNs to just anybody.

Second, the brother's own tax forms must agree with your claim: So if you do not have the person's consent, no go. The classic collision (old tax forms) is when a parent claims a child as a dependent to collect the $1000-ish in tax benefits, and the child also claims 1 exemption to collect the $300-ish in tax benefits. The child was typically very strident about collecting that $300, with not a care for the knock-on effects.

Also, pay great heed to Mhoran's point about financial aid.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .