How would you choose......?

imagine the baby you bought back from the hospital an loved you saw there first smile heard there first laugh....than one day somone turns up on the doorstep to tell you sorry the hospital stuffed things up thats not your baby your babys here would you choose the baby that grew in you for 9 months that you saw on the ultrasound bonded with an felt kick an roll or would you choose the baby that you have with you now??