Trivia: Ruby (Genevieve Cortese), is married to Jared Padalecki. They have 2 sons.
Trivia: Dean's guiding angel Castiel is also the angel of Thursday. Fitting, since Supernatural airs on Thursdays in the U.S.
Trivia: In 'After School Special' Dean says the the regular gym teacher is getting married in Massachusetts. This is a reference to how female gym teachers are thought to be gay. At the time of the airing of this episode Massachusetts was the only state in the U.S. that allowed gay marriage.
Answer: Angels themselves may not have genitalia, but their vessels do. Nephilim occur when an angel in a vessel reproduces.
Greg Dwyer