Mothers from the Manchu minority ethnic group, as only researched in the 1900s in Aigun of Northern Manchuria where the researcher S. M. Shirokogoroff personally believed the Manchu element were "purer" than those of Southern Manchuria and Peking, used to show affection for their children by performing fellatio on their male babies, placing the penis in their mouths and stimulating it, while they regarded public kissing with revulsion.