Sorry-----only couples who are legally married can file a joint tax return. If you and your GF are all living together with your child as a family, then one of you files as Single and does not enter anything at all about the child on your return, and the other one files as Head of Household and claims the child as a qualifying dependent. It is usually best for the one with the highest AGI to file as HOH. The child's SSN cannot be used on both of your tax returns---it can only be entered on one of your returns.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
