Cao Cao’s second son is Cao Shuo.
Cao Shuo is the half-brother of Cao Cao’s eldest son, Cao Ang. Cao Ang's biological mother, Cao Cao's concubine Liu, died young, so Ang was raised by Cao Cao's wife, Mrs. Ding. The mother-son relationship between Mrs. Ding and Cao Ang was very good. Cao Ang later died in battle, which made Mrs. Ding very sad. Later, Mrs. Ding was deposed because of this incident. Cao Shuo, who was born to the same mother as Ang, should not be much younger than Ang because his biological mother Liu died early. Cao Pi, the son of Cao Cao's other concubine Bian, was ten years younger than Cao Ang, so the age difference was quite large. According to historical records, Mrs. Ding regarded the Bian family as "mother and son insufficient". At that time, the Bian family only gave birth to one son, Cao Pi, while Mrs. Ding had two sons, Cao Ang and Cao Shuo, and a daughter, Princess Qinghe (also born to the Liu family). From the name analysis, Cao Cao's four eldest sons were named Ang, Shuo, Pi, and Zhang respectively. These four characters all have the meaning of showing off. The characters for Cao Pi and Cao Zhang are "Zihuan" and "Ziwen" respectively. Huanwen is actually the Qihuan and Jinwen of the Five Hegemons of the Spring and Autumn Period. This explains the meaning of Cao Cao's name. On the other hand, "Huanwen" is often used Said together, it shows that the order of the two brothers Cao Pi and Cao Zhang is close. If Cao Shuo is younger than Cao Pi, he must be younger than Cao Zhang, but in this case the theory of "mother and son are not enough" is not valid, and the theory that Liu died early does not exist.
Therefore, Cao Pi cannot be older than Cao Shuo. Cao Shuo is Cao Cao's real second son.