Because it's an RFIE, i am assuming they did not see that copy of the BC. If they had seen that, they would have sent an RFE for secondary evidences due to the late registration/issue of the certificate.   To avoid another RFE or denial (uscis has been denying bunch of cases without issuing any RFEs), my suggestion: Respond to the RFIE with the following: 1. Copy of the BC   Because the birth certificate was issued lots of years after the birth, you need to provide