Do Cheng know his birth mother?
Yes According to Cheng's personal profile, Cheng joined China on 1956 and found his biological mother for 30 years in the same year, so Cheng and his biological mother recognized each other on 1956. Cheng, male, Han nationality, party member of the Jiu San Society of the Communist Party of China, academician of China Academy of Sciences, famous theoretical physicist, winner of the "Two Bombs and One Satellite" Meritorious Medal.