Harold Clayton Urey was born on April 29, 1893, in Walkerton, Indiana, the son of Samuel Clayton Urey, a school teacher and a minister in the Church of the Brethren, and his wife Cora Rebecca née Reinoehl. He had a younger brother, Clarence, and a younger sister, Martha. The family moved to Glendora, California after Samuel became seriously ill with tuberculosis, in hopes that the climate would improve his health. When it became clear that he would die, the family moved back to Indiana to live with Cora's widowed mother. Samuel died when Harold Urey was six years old.