Al-Marghinani

The Hedaya
(principles of law according to Hanafi law tradition)

Book on Divorce

Chapter on Impotence

[As presented in this chapter, the law says that if a woman accuses her husband of being impotent, the judge shall set a probationary period of one year for him to prove that it is not true, and if he fails, she can obtain a permanent separation on those grounds. A curious provision in the chapter makes a distinction between castrated men and eunuchs, giving "eunuchs" the same rights as "impotent men", while taking those same rights away from "castrated men." This type of distinction is familiar from the Roman laws almost a thousand years before.]
 

... And if he is a castrated man [majboob], there shall be an immediate separation between them, if she wishes, because there is no use in waiting. And as for a eunuch [khasee], they shall wait as they wait for an impotent man ['ineen], because there is hope that he can have sexual intercourse with her.