Heinrich and Irene Wiens were fined €2,340 after withdrawing four of their children from the classes and a mandatory interactive play in 2006 because they felt the content of the lessons went against their Christian beliefs.

Although school officials contended that the play’s purpose was to prevent the sexual abuse of children, the Wiens felt that the play encouraged children to become sexually active and follow their sexual feelings.

When the programmes were running, the Wiens kept their children at home and instructed them according to their own Christian values on sexuality.

When they refused to pay the fine on moral and legal grounds, they were sentenced to 43 days in jail. Mr Wiens already served his term last year, while Mrs Wiens has just begun her sentence.

The Alliance Defense Fund argues that the German state has acted unlawfully in imprisoning and fining the Wiens. It is seeking an intervention by the European Court of Human Rights to secure Mrs Wiens’ immediate release from prison.

Roger Kiska, ADF legal counsel, said: “Parents, not the government, are the ones ultimately responsible for making educational choices for their children, and jailing them for standing on this universal right is simply unconscionable.

“Irene Wiens was well within her rights under the European Convention of Human Rights to opt to teach her children a view of sexuality that is in accord with her own religious beliefs, instead of sending them to four days of classes and an interactive play that she found to be objectionable.”