Although he had an older paternal half-brother named Hojumaru (Tokisuke HOJO), Shojumaru (Tokimune HOJO) was determined to be the heir because Hojumaru was born from a concubine (thus an illegitimate child).
異母兄に宝寿丸（北条時輔）がいたが、宝寿は側室の子（庶子）であったため、正寿が後継者に指名された。