Why did they suddenly find her and make sure she was her daughter?

Think of Chen Shirley suddenly reaching for the birthmark behind her. Did they recognize her as Tang's daughter by this birthmark?

sees her run to the bathroom back to the mirror, twisting her head to look at her back, this birthmark was born to her, this is not fake, is he really the daughter of the Tang family?

Chen Shirley recalled or decided that all these speculations were in vain. As a doctor, she still felt that paternity testing was the most reliable.

Should you tell the old woman and take her to a paternity test? It's...