The two are being held without bail in Sarpy County Jail on felony charges of sexual assault and incest.
The Associated Press is not using their names, to protect the privacy of the boy.
Public defender Tom Strigenz represents the mother and says she maintains her innocence. The father’s attorney has not responded to a message.
An arrest warrant affidavit says the mother told in-laws in September that she and her husband had sexually assaulted the boy. The document says she said she participated in the assaults so she could save her marriage.
A hearing is scheduled March 18 for both parents. They live in Bellevue.