U.S. soldiers who liberated a Nazi concentration camp in April 1945 were amazed to discover, among the countless famished and dead, seven Jewish mothers and their babies, who had somehow avoided execution or starvation.

This week, six of those former babies are to gather for an emotional reunion at Dachau on the outskirts of Munich.

German television is to air a television documentary which explores the miracle of how these three infant boys and four infant girls slipped through the cracks of the Nazi killing machine.

George, Jossi, Leslie, Marika, Agnes, Judit and Szuzi spent the first months of their lives in Kaufering I, a camp 50 kilometres west of Munich.

Marika Novakova, 65, never understood when she was growing up in the Slovakian small town of Dunajska Streda why her birth certificate said she had been born in Kaufering, a village in Bavaria. It did not make sense, but her mother refused to explain why.

A couple of documentary makers employed by German broadcaster WDR, Eva Gruberova and Martina Gawaz, asked the mother for an interview, but Eva Fleischmanova refused. Finally she re-considered. As the cameras filmed, she unveiled her past.

Fleischmanova describes the horrors of the war, how she was nearly gassed at Auschwitz and ended up in Kaufering. She tells of her daughter's birth in captivity, and how she kept her personal Holocaust story secret because of anti-Semitism in Slovakia.

Miriam Rosenthal, 87, can barely bring herself to speak in some sections of the documentary. Holding her son Leslie, she can be seen with Fleischmanova in the extraordinary, 65-year-old, black-and-white photo of the young mothers between bunks in a dormitory.

The two woman documentary makers began their research using that photo.

Miriam Rosenthal's description of the war years on camera is the first time she spoke German again after leaving Germany for Canada.

She and her husband, also a Holocaust survivor, built a new life for Leslie and themselves in Toronto.

The horrors of the past still loom over Miriam, who often breaks into tears as she speaks.

"As a girl, I imagined I had been born in a forest," says Marika Novakova. "All my mother would tell me was that people were treated very cruelly there. I did not know what sort of place it was at all."

The documentary makers take Marika on a journey to the way-stations of her mother's ordeal: to the fence at Auschwitz, to the German city of Augsburg where the women were used as slave labour in a arms factory, and to Kaufering I.

Dachau concentration camp had several satellite camps like Kaufering where slave labour was kept close to factories.

Marika's mother was twice inspected by Josef Mengele, the doctor of death at Auschwitz, as he selected those to be killed and those to be kept for labor. He pinched her breast to see if milk came out.

Eva Fleischmanova somehow managed to hold in her belly so that he did not notice she was pregnant.

Heinrich Himmler, head of the SS, was determined to exterminate all Jewish children. His policy was set out in the secret speech he gave at Poznan, Poland on October 6, 1943.

"I do not consider it justifiable to exterminate the men, meaning to kill them or get them to be killed, while allowing the revengers, in the form of children, to grow up and face our sons and grandsons," said Himmler.

The Nazis deliberately killed children: the toll of minors in the Holocaust is estimated at as much as 1.5 million.

Miriam Rosenthal also remembers the moment when she narrowly escaped being put to death.

"An SS man came round with a loudspeaker and he was shouting, 'All the women come outside. You've been given a double ration of bread.'"

Most of the women obeyed, but Rosenthal stayed indoors. A voice inside told her to stop. "All those women ended up in the crematorium," she said.

Rosenthal was shipped from Auschwitz to Kaufering at the age of 22.

The young mothers survived in Kaufering thanks to the solidarity of other women prisoners, who cared for the newborns when the mothers were summoned to work. Fellow prisoners hid the babies and gave them water and food.

The seven mothers and their babies scattered after the Second World War. It was Rosenthal who re-opened a connection by sending a copy of the black-and-white photo to her former fellow inmate Fleischmanova.

The daughter Marika saw the picture and resolved to fly to Canada to meet Rosenthal to hear the story of her first weeks of life.

"I would never have dreamed I would see little Marika again," Rosenthal said.

Six of the seven former concentration camp babies are to attend the reunion - their first - at Dachau this Thursday for the opening of a special exhibition on the fate of mothers in the Dachau camps. Germany's ARD television is to air the documentary Wednesday.