[5] He was the second of four children born to socialite Martha Stewart Bulloch and businessman and philanthropist Theodore Roosevelt Sr. He had an older sister (Anna), a younger brother (Elliott) and a younger sister (Corinne).[6] Elliott was later the father of Anna Eleanor Roosevelt who married Theodore's distant cousin, Franklin Delano Roosevelt. His paternal grandfather was of Dutch descent;[7] his other ancestry included primarily Scottish and Scots-Irish, English[8] and smaller amounts of German, Welsh, and French.[9] Theodore Sr. was the fifth son of businessman Cornelius Van Schaack "C. V. S." Roosevelt and Margaret Barnhill as well as a brother of Robert Roosevelt and James A. Roosevelt. Theodore's fourth cousin, James Roosevelt I, who was also a businessman, was the father of President Franklin Delano Roosevelt. Martha was the younger daughter of Major James Stephens Bulloch and Martha P. "Patsy" Stewart.[10] Through the Van Schaacks, Roosevelt was a descendant of the Schuyler family.[11]
Roosevelt's youth was largely shaped by his poor health and debilitating asthma. He repeatedly experienced sudden nighttime asthma attacks that caused the experience of being smothered to death, which terrified both Theodore and his parents. Doctors had no cure.