It is now generally considered as the actual and correct genealogy that "Tokitane was the eldest son of Tanetsuna and the elder brother of Yasutane," because those descriptions in "Genpei Tojoroku" (a record of Genpei battles) considered to be authored by the members of the Chiba clan in late Kamakura period and stating the title of the Chiba clan to be successively passed down to the eldest son of the Chiba family would be inconsistent, or the fact that Yasutane could not take over the Chiba clan after Tanetsuna's death even though he was the "elder brother" would be inexplicable.
また、時胤が胤綱の長男でないとした場合、鎌倉時代後期に千葉氏関係者によって書かれたと言われている『源平闘諍録』に千葉氏の当主が長男に継承され続けたとする記述との矛盾や胤綱の没後「兄」である泰胤が千葉氏を継承できなかったことの説明が付かないという点で問題点が発生するため、「時胤は胤綱の長男・泰胤の兄」が実際の正しい系譜であると考えられている。