I didn’t have an older sister, but my younger brother was there.
My younger brother is in his late 30s and still has soft ligaments on his wrist.
My sister and I belong to the 3%.
There are also Caucasian peoples who have Mongolian spots. The Bulgarians are the main characters, and there is a theory that the original Bulgar family, the progenitors of the Bulgarians, came from the East. Although the frequency is very low, Mongolian spots are also observed in infants of black Negroid descent.
The Mongolian spot is a code that confirms the homogeneity of the Mongoloid races scattered around the world, but it is also a very unfamiliar mark to Westerners. There is an anecdote that when a Korean couple who went to Gumi gave birth to a baby, Western doctors and nurses were worried because ‘the baby had bruises on the buttocks’, while in Europe, an Asian baby’s Mongolian spot was mistaken for domestic violence and was reported. What happened actually happened.
Mongolian spots are blue spots that occur when melanin pigment cells that migrate to the epidermis during early embryonic development remain in the dermis. As melanin pigment cells in the dermis gradually disappear at birth, Mongolian spots begin to disappear from 4 to 5 years of age and disappear completely by age 13.
If it remains even as an adult, it is not a Mongolian spot but a pigmented disease called ‘Ota nevus.’ This mole, first named by Japanese doctor Mr. Ota and called Ota’s nevus, is a bluish mole that mainly occurs around the eyes, temples, forehead, and nose.
In the case of white people, the melanin pigment in the skin is too little, and on the contrary, in black people, the melanin pigment is excessive, so even if Mongolian spots are present, they are covered by pigment on the front and back and are difficult to notice. Therefore, even if Caucasian babies are sometimes born with Mongolian spots, they are not as vivid as those of Asians, and Mongolian spots are not a special mark imprinted only in the genes of East Asians.
Recently, Professor Shin Son-moon’s team from the Department of Pediatrics at Kwandong University Cheil Hospital conducted a survey of 1,964 newborns born to Korean parents between 2012 and 2013, and found that Mongolian spots were observed in 97.1% of them.
For Japanese people, the incidence of Mongolian spot is 81.5%, for Chinese people it is 86.3%, and for American Indians it is only 62.2%. The incidence of Mongolian spots in newborns in Korea is more than 10% higher than the rate in newborns in Japan or China, which are of the same Mongoloid origin.
The most common location of Mongolian spots was the buttocks and torso at 97.3%, followed by the arms at 1%, the legs at 0.8%, the chest and back at 0.7%, and the head and neck at 0.2%. Professor Shin Son-moon, who conducted this study, emphasized that “just because the incidence of Mongolian spots is high, it is difficult to interpret that we are of pure Mongolian descent.”