Mongolian Blue Spot（蒙古斑）

99.5% of Japanese babies (and majority of Mongolian, Korean babies etc.) has blue spot on buttocks. It disappears naturally in 3-5 years

One of my friends who gave birth in England had bad experience about it.
Doctors in England didn't know the Mongolian Blue Spot and they thought it was a stigma because of abuse!
It seems there are many cases like that.

http://www.tokyo-med.ac.jp/genet/msp/index.htm

そういえば志門に蒙古斑があるのか気になり、ちょっとお尻を見てみたところ、薄いものが左側にだけあるようです。
ちなみに、イギリスで出産した友達は、お医者さんが蒙古斑を知らなかったために、虐待によるあざと間違えられて大変だったそうです。


Other baby's blue spot
蒙古斑（例）



Simon's buttocks
志門のお尻

He has spot only on left side.