Throughout history, there is the generally known theory of 'female Emperor's temporarily succeeding' to avoided the discontinuation of the Imperial lineage (Imperial male line), and to keep the Imperial succession in the male line.
歴史学界では、女性天皇は皇統（皇室の男子血統）の断絶を忌避し、男系での継承を維持したという「女帝中継ぎ論」が通説である。