Wu was born Wu Tairan in Wujin County, Jiangsu, on January 22, 1917, the second of four sons of Wu Jingyi (Chinese: 吴敬仪), a Chinese businessman.[2] His elder brother Wu Ruiping (Chinese: 吴瑞萍) and younger brothers Wu Weiran (Chinese: 吴蔚然) and Wu Anran (Chinese: 吴安然) are also medical scientists.[2] Wu was raised in Tianjin. He earned a Bachelor of Science degree from Yenching University in 1937 and a Doctor of Medicine degree from Peking Union Medical College in 1942. He studied urology under Xie Yuanfu (Chinese: 谢元甫). He was accepted to University of Chicago in 1947.[citation needed]
Wu was twice married. He married his first wife Zhao Junkai (Chinese: 赵君恺) at the age of 16 when he was a student in Yenching University, she died in 1978.[2] A few years later, he married Gao Rui (Chinese: 高睿).[2]