
Can somebody help me understand what happen with the sperm samples, did it got mixed?

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.
This is so awesome!!!!! I love the story so much