The only parent with the automatic right to claim a newborn as a dependent is the parent where the child physically lived (regardless of court orders) more than half the nights of the year since it was born. This parent should select that the child lived with them "all year" in Turbotax to avoid confusion, this will create a correct tax return.
The parent where the child physically lived less than half the nights of the year has no right to claim the child as a dependent unless the custodial parent gives the non-custodial parent a signed form 8332 dependent release.
The IRS does not involve itself in custody disputes, and will award the dependent to you solely based on physical custody, if you don't sign the form. However, if you don't sign the release form, the other parent can go back to the family court and ask that you be held accountable. I do not advise ignoring a court order unless your attorney advises you to do so.
