[3] Her father, Ko Gyon-tek, worked in an Osaka sewing factory run by Japan's ministry of war,[9][10] a 16th-generation descendant of the Joseon scholar official, Go Deuk-jong.

[12] Her younger sister Ko Yong-suk sought asylum from the U.S. embassy in Bern, Switzerland, while she was living there taking care of Kim Jong Un during his school days, according to South Korea's National Intelligence Service; U.S. officials arranged Ko Yong-suk's departure from the country without consulting South Korean officials.

[17] Under North Korea's songbun ascribed status system, Ko's Korean-Japanese heritage made her part of the lowest "hostile" class.

Furthermore, her father worked in a sewing factory for the Imperial Japanese Army, which gave her the "lowest imaginable status qualities" for a North Korean.

[3] The building of a cult of personality around Ko encounters the problem of her bad songbun due to her Japanese mother, even though it is usually passed on by the father.