Sima Yu's father Sima Zhong was developmentally disabled, and before he, then crown prince, was to marry his wife Jia Nanfeng, Zhong's father Emperor Wu gave him one of his own concubines, Consort Xie Jiu (), so that Consort Xie could teach him how to have sexual relations. While Crown Princess Jia bore the crown prince four daughters, Sima Yu was his only son.
