What Is and What Should Never Be - S2-E20
Audio problem: Dean is in the cemetery talking to his father's grave, trying to figure out what's happening to him. In a continuous shot, right after Dean says "like it doesn't want me to be happy", you hear him say, "of course I know what you'd say" but his mouth doesn't move at all. (00:23:00)
Answer: Angels themselves may not have genitalia, but their vessels do. Nephilim occur when an angel in a vessel reproduces.
Greg Dwyer