Imperial Princess Teishi (Yoshiko/Sadako) was born while the relationship of her grandfather, Michinaga and her father, Emperor Sanjo was not going well, therefore Michinaga was not happy having a baby girl since he was expecting to have baby boy as a future Prince to improve the relationship with the Emperor.
禎子内親王の誕生は祖父道長と父三条天皇の間がしっくりいかない最中のことであり、それだけに皇子誕生で関係改善を期していた道長は女御子であったことに不機嫌であった。