The adultery theory was thus spread based on the fact that, as pointed out by some researchers, the extinguishment of the imperial line of Emperor Tenmu, caused by the death of Empress Shotoku, enabled the revival of the imperial line of Emperor Tenchi, and therefore it is likely that people on Emperor Tenchi's side needed to deliberately and unfairly insult the Empress and Dokyo so as to justify the succession of the imperial throne by the imperial line of Emperor Tenchi.
こうした説が流布された背景には、称徳天皇の死をもって天武天皇系の皇統が断絶して天智天皇系の皇統が復活した事から、天智天皇系の皇位継承を正当化するために天皇と道鏡を不当に貶めるためという指摘がある。