The little girl had been taken from her parents’ care when she was 31 days old after concerns were raised about her safety, Judge Patricia Lynch was told.
Social services staff had registered her birth “just with her surname” and had chosen an “appropriate first name” for use on a “day-to-day basis”, the judge heard.
Details of the case have emerged in a ruling by the judge following a private family court hearing in Leeds.
Judge Lynch said the family involved could not be identified.
But she said the local authority with responsibility for the girl’s welfare was Leeds City Council.
A judge concluded – during earlier separate family court proceedings – that the girl’s father had sexually assaulted another child, Judge Lynch was told.
Judge Lynch said she was satisfied that the little girl would be at “risk of sexual harm” if she stayed with her parents.
She said the youngster should be placed for adoption.
The judge said the couple had been involved with social services staff before.
And she said they had “concealed” the little girl’s birth from social workers.
The girl’s mother had given “false information” to hospital staff and given birth under an assumed name, said the judge.
Judge Lynch said the child had been placed in foster care after being taken from her parents during the summer.