A brother and sister who fell in love and had four children together have continued their call for incest laws to be revoked, so their relationship can be legally recognised.

Patrick Syuebing was moved into a foster home in East Germany when he was attacked by their father decades ago.

After more than 20 years, he reunited with his younger sister Susan Karolewski.

Six months after re-discovering his biological family, Patrick, who was 23 at the time, and Susan, who is mentally disabled, began sharing a bedroom after their mother, Ana Marie, died.

Their illegal pairing has since produced four children, two of whom are severely disabled.

In 2001, the couple began trying to change Germany’s laws that makes sex between siblings illegal. In 2012, they took their case to the Court of Human Rights.

At the time, Patrick was reported as saying: “We do not feel guilty about what has happened between us. I became head of the family and I had to protect my sister.

“She is very sensitive but we helped each other during this very difficult period and eventually that relationship became physical. We didn’t even know we were doing anything wrong when we started sleeping together. We didn’t think about using a condom.

“We didn’t know it was illegal to sleep together.”

Patrick added that their mother would “not have approved” of the relationship between him and his sister, the Mirror reported.

Susan defended the relationship she has with her brother, saying: “We didn’t know each other in childhood, it’s not the same for us. We fell in love as adults and our love is real. There is nothing we could do about it.

“We were both attracted to each other and then nature took over from us. It was that simple. What else could we do? We followed our instincts and our hearts.”

The couple have taken their case as far as the High Court, with Patrick serving time for breaking German incest laws.

Patrick has subsequently undergone a vasectomy in a bid to change the minds of courts to allow him to live with his sister without the risk of further jail time.