Even those who support the view that the family actually lived and owned the land in the Mutsu Province do not entirely consider the genealogical tables as trustworthy historical resources, and there still remains doubt about whether Tanemitsu actually existed.
領有・移住を肯定する説の論者にとっても諸系図の信頼性は低いので、やはり胤光の実在性には疑問が残る。