If I am not claiming my son Justin as a dependent why do you need his social security number ?

[MichelleT]

Is there a reason he is on your return if you are not claiming him?

[GinnyF]

It is possible to need the social security number of a person in your household who would be your dependent except they made too much money.

That person can possibly qualify you for head of household status which has lower income taxes and higher deductions allowing you to pay less in taxes.

If the interview asks you for the social security number of the qualifying person, entering it allows Turbo Tax to check to see if qualify for certain tax benefits.