After unsuccessfully petitioning his father for two years to marry the girl, the man heated up a knife and sliced off his reproductive organ, said a police official.
The young man came from a prominent family in the southern Egyptian province of Qena, one of Egypt's poorest and most conservative areas that is also home to the famed ancient Egyptian ruins of Luxor.
The man was rushed to the hospital but doctors were unable to reattach the severed member, the official added citing the police report filed after the incident.
The official, who spoke on condition of anonymity because he was not authorized to speak with the press, added that the man was still recovering in the hospital.
Traditionally, marriages in these conservative part of southern Egypt are between similar social classes and often within the same extended families -- and are rarely for love.