Preface to the biography of Lanting by Zhen Huan.

Because he has no son, he can make room for Hiro after Yuan Che's adoption. In the original book, Zhen Xuan's second sister yaoyu and third sister Yu Rao gave birth to a daughter, while the illegitimate daughter Yu Yin (Huanbi) of the side princess had no children. Zhen Xuan's brother Zhen Heng and his ex-wife's son were killed by An Lingrong, and the second princess's wife gave birth to several daughters. Zhen Xuan was pregnant with five children and only gave birth to 1 son and three daughters. Generally speaking, Zhen Xuan gave birth to several sons.