Feng changed the sample with his own... The MC sample was frozen but some chapters ago it was stolem
Jinyao secretly replaced Yiyun's sperm sample with his during the insemination, so Rourou is biologically Jinyao's kid. Yiyun's actual sperm sample is currently stolen by some ppl who thought Yiyun's sperm sample was Jinyao's because Jinyao took and was holding onto Yiyun's sample. It doesn't get brought up again after that so I don't know if ML2 ever got Yiyun's sample back.
Stolen*
Feng purposely switch his sperms with Yiyun back then which Yiyun still doesnt know. He just knew that Rourou is not his and might thought it was accidentally switch. While Yiyun sperm is still stored under Feng's name but now it got stolen.
Can somebody help me understand what happen with the sperm samples, did it got mixed?