Gates was born on October 28, 1955, in Seattle, Washington, to William H. Gates, Sr. and Mary Maxwell Gates, of English, German, and Scotch-Irish descent. His family was upper middle class; his father was a prominent lawyer, his mother served on the board of directors for First Interstate BancSystem and the United Way, and her father, J. W. Maxwell, was a national bank president.

Gates has one elder sister, Kristi (Kristianne), and one younger sister, Libby. He was the fourth of his name in his family, but was known as William Gates III or "Trey" because his father had the "II" suffix. Early on in his life, Gates' parents had a law career in mind for him. When Gates was young, his family regularly attended a Congregational church.

Bill Gates' Family Tree