A German man has claimed his relationship with his sister is ‘real love’ as he campaigns for incest to be made legal.

Patrick Stübing, 44, fathered four children with his younger sister, Susan Karolewski. He was adopted as a child but tracked down his biological family when he was 23. His mother then took him in and asked he shared a room with his then 15-year-old sister.

‘’Trust grew into a different type of love when our mother died six months later.’’ Susan said.

Stübing and Karolewski struck up a physical relationship and, between 2001 and 2015, had four children together. Two of the children are disabled and adopted by the state.

Stübing told newspaper: ‘She is very sensitive but we helped each other during this very difficult period and eventually that relationship became physical.’

Stübing claimed the pair ‘didn’t even know they were doing anything wrong’ as incest was not illegal in Germany at the time.

When incest became illegal in Germany, the pair were tried for incest in 2002, and a district court heard Stübing ‘only at the beginning bothered using condoms’.

They took their challenge to the Court of Human Rights in 2012 and lost.

Countries such as France, Turkey, Japan and Brazil have already legalised sex between relatives while incest is punishable by death in the likes of Afghanistan, Iran, Saudi Arabia and Nigeria.

The practice is also illegal in the UK.