No one in this user forum can give you advice about the possible effect on your government benefits if someone else claims your child as a dependent. We cannot help with questions about child support, other than to inform you that child support paid is not deductible, nor is child support taxable. We cannot answer questions about your messy paternity issue or your marital status. We can only answer questions about preparing income tax returns or about using the tax preparation software.
As for the bio-dad claiming the child-----the IRS cares about physical custody. The IRS considers the "custodial parent" to be the parent with whom the child spent the most nights---at least 183 nights. You mention "shared" custody, but we do not know what that means to you.
The non-custodial parent can get the child tax credit for a child under the age of 17, but cannot use the child to get earned income credit or to file as head of household. The custodial parent can get earned income credit, the childcare credit, and file as head of household. The child-related credits are based on having income from working.
**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.**
