Kurt Donald Cobain was born on February 20, 1967, at Grays Harbor Hospital in Aberdeen, Washington, to a waitress, Wendy Elizabeth (née Fradenburg) (born 1948), and an automotive mechanic, Donald Leland Cobain (born 1946). His parents were married on July 31, 1965 in Coeur d'Alene, Idaho. His ancestry included Irish, English, Scottish, and German. Cobain's Irish ancestors migrated from County Tyrone of Northern Ireland in 1875. Researchers have found them to have been shoemakers, originally named Cobane, who came from the village of Inishatieve near Pomeroy, settling in Cornwall, Ontario, Canada, and then in Washington. Cobain himself believed his family came from County Cork in southern Ireland. Cobain had one younger sister named Kimberly, born on April 24, 1970.
When Cobain was seven years old, his parents divorced. Later in his life, he said the divorce had a profound effect on his life. His mother noted that his personality changed dramatically; Cobain became defiant and withdrawn.
Cobain's parents both found new partners after the divorce. His father had promised not to remarry; however, after meeting Jenny Westeby, he did, to Kurt's dismay. Kurt, his father, Westeby, and her two children Mindy and James, moved into a new household together. Cobain liked Westeby at first, who gave him the maternal attention he desired. In January 1979, Westeby gave birth to a boy, Chad Cobain. This new family, which Cobain insisted was not his real one, was in stark contrast to the attention Cobain was used to receiving as an only boy; he soon began to express resentment toward his stepmother. Kurt's mother began dating a man who was abusive. Cobain witnessed the domestic violence inflicted upon her, with one incident resulting in her being hospitalized with a broken arm. Wendy steadfastly refused to press charges, remaining completely committed to the relationship.