Given the following context:  The film follows a diverse group of mostly middle-class Los Angelenos through the emotional ups and downs in their flawed yet very human lives, each loosely connected to each other through a restaurant. In the first story, Mamie reluctantly agrees to work with a would-be young filmmaker in order to locate the now grown son she secretly gave up for adoption after becoming pregnant from her stepbrother Charley – who is later revealed to be gay – 19 years earlier. In the second story arc, her stepbrother, and his domestic partner, Gil, are deciding whether or not to confront their friends, a lesbian couple (Laura Dern and Sarah Clarke), regarding the paternity of their son. And in the third, a young man, Otis, is involved with a band and trying to keep his father, Frank, from learning that he is gay, while also dealing with the seemingly gold-digging woman, Jude, who inserts herself into their lives.  answer the following question:  Who is the gay man that fathered Mamie's son?
A:
Charley