The problem in "Désirée's Baby" is the apparent racial mix of the baby born to Désirée and Armand.
When Madame Valmondé visits her daughter in her new home with Armand Aubigny, who is from a pestigious family, not long after their baby is born, she enters the boudoir and finds Désirée lounging on her chaise with the baby at her breast. Mme.Valmondé turns to the baby after greeting her adopted daughter, then exclaims, "This is not the baby!" Désirée believes that her mother is struck by the size of the baby boy, and mentions how he has grown.
Mme. Valmondé scanned the baby narrowly, then looked as searchingly at Zandrine, whose face was turned to gaze across the fields. “Yes, the child has grown, has changed....”
There is a skepticism in the response of Mme. Valmondé because she worries that her daughter who was a foundling left so many years ago at the big stone pillar of the Valmondé mansion may be bi-racial. Some time later, Armand begins to act differently toward her; he is distant in his manner and avoids her company. After the baby is three months old, Désirée is stricken by the resemblance of the baby to the quadroon [one-fourth black]boy who fans her. Startled by the comparison, she dismisses the boy. When Armand does come into her room, she asks him to look at the baby and tell her what it means. He replies with coldness that it means the baby is not white, nor is she.
“It is a lie; it is not true, I am white! Look at my hair, it is brown; and my eyes are gray, Armand, you know they are gray. And my skin is fair,” seizing his wrist. “Look at my hand; whiter than yours, Armand,” she laughed hysterically.
Désirée writes to her mother, who encourages her to come home. However, the despairing young mother takes her baby and walks out in her peignoir through the willows that lie along the shore of the bayou and is seen no more. Her act is one of desperation and despair, a needless act because it was Armaud's blood that contained Negro. In a letter found in a drawer, among those of Désirée is one from Armand's mother, a nurse, thanking God that Armaud does not know hardship nor that his poor mother has been descended from slaves.