The film by Anne Zohra Berrached, 33, tackles a thorny issue in a country in which, according to the producers, more than 90 percent of parents terminate pregnancies in which the foetus is severely disabled. The subject, however, is rarely discussed.
The picture, set in ex-communist east Germany, tells the story of a cabaret performer and her manager husband who already have one child and learn she is pregnant with a second.
However the pair, Astrid and Markus, discover during a prenatal examination that the child will have Down syndrome. Later, in the sixth month of pregnancy, they hear that the boy has congenital heart problems that will require multiple surgeries he may not survive.
Teams of specialists, all played by actual doctors, offer advice to the couple based on their medical expertise. But they leave the parents to wrestle with the complex ethical questions about whether to have the child.
The film presents a society in which religion hardly plays a role but where the abuses under Adolf Hitler, in which 300,000 ill and disabled people were systematically murdered by the Nazis, loom large.
When a babysitter speaks critically of severely disabled children and wonders aloud whether their lives are worth living, Astrid attacks her as a "fascist".
The weight of the choice begins to strain the couple's marriage and their relationship with Astrid's mother, who moves into care for their daughter.
"It was very important for me to do a film which concerns primarily the conflict of making a decision as a couple," Berrached told reporters.
"That's what I wanted to focus on. I didn't want to do a segment for a television news show or something like that."
Berrached, who finished the picture as part of earning her film degree, said the team had spoken to three women who had faced similar choices.
The filmmakers admitted after a well-received press preview that the subject remained a taboo in Germany and could scare off potential distributors in more socially conservative countries such as Poland and Italy.
Astrid is played by Julia Jentsch, 37, who won the festival's Silver Bear best actress prize in 2005 for her turn as a Nazi resistance martyr in "Sophie Scholl - The Final Days".
Critics said she could also be a frontrunner for acting honours this year on awards night Saturday, when a jury led by actress Meryl Streep hands out the prizes.