A nurse is caring for a client who is at 20 weeks of gestation and asks what could cause the infant to have a cleft lip. Which of the following responses should the nurse give?

A cleft lip is caused by the Epstein-Barr virus (EBV)."

"A cleft lip is due to an abnormal autoimmune response."

"A cleft lip is due to advanced maternal age.”

"A cleft lip has a genetic component."