The rule in Lousiana that applies to the birth certificate is this: “(ii) If a child is born outside of marriage, the full name of the father shall be included on the record of birth of the child only if the father and mother have signed a voluntary acknowledgment of paternity or a court of competent jurisdiction has issued an adjudication of paternity.” Louisiana Revised Statutes (L.R.S.) section 40:34(B)(1)(h)(ii). The Form for the acknowledgement requires that you and your boyfriend specifically state that he is the biological father of the child. You’ll find the form here: acknowledgement of paternity form. Note that this form cannot be completed until after the child is born. Since you know another man to be the father of this child, you cannot legally sign the attestation because by doing that you are attesting to something you know to be untrue. That in turn means you cannot get you boyfriend’s name on the birth certificate as the child’s father.
As you are not married, the hospital should also have you complete a separate paternity information form in which you provide information about the biological father. This information is then used to notify the father and results in notifying the named father of the birth and notifying the child support enforcement office, too. L.R.S. § 40:34(E). Thus, it starts the process of setting the father up for a child support obligation. Again, you are required to provide accurate information on the biological father for this.
It is not a good idea to list someone as the father on these documents when you know he is not the father. There are other ways to deal with the concerns you have regarding the biological father.

