St. Marina the Monk
St. Marina's mother died when she was young, and in his mourning, her father decided to give all he had to the poor, marry off Marina, and become a monk. Marina didn't want this and convinced her father to let her join the monastery with him as a man, calling herself Marino. Nobody in the monastery knew that their new brother was actually a woman, and Marino developed a reputation for extreme piety, humility, and holiness.
However, one day Marino and some of the other monks were sent on a trip, during which Marino was accused of fathering the child of an innkeeper's daughter. Though this was obviously impossible, the monk chose to accept exile as punishment rather than reveal herself as a woman. When the child was born, she adopted him and raised him as her own, feeding the baby with sheep milk. Eventually Marino and the child were accepted back into the monastery. The child became a monk himself, and Marino lived there until he died, whereupon his brothers finally learned his secret, realizing immediately that the accusation that had so long led to challenges for Marino was indeed false.