The story, which has drawn more than 110 million views on China’s social media platform Weibo, comes from Jiangsu Province, where the girl's parents said her appearance was so unexpected that they once wondered whether a hospital error had occurred.
DNA tests later confirmed the child is biologically theirs, the South China Morning Post reported.
Tracing the family's lineage revealed the explanation. The girl's great-great-grandfather was Slavic, from Russia. Over several generations, the family had only male descendants who inherited dominant Han Chinese traits such as black hair and dark eyes. In this generation, however, recessive genes from that distant ancestor resurfaced in the couple's daughter.
According to genetic experts cited by Yangcheng Evening News, black hair and dark eyes are dominant traits, while blond hair and blue eyes are recessive and can remain hidden for generations.
The reappearance of such contrasting features after many decades is rare and requires an unlikely combination of genes. Specialists estimate the child carries about one-sixteenth Slavic ancestry.