Given the task definition and input, reply with output. In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: 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.
Who is the gay man that fathered Mamie's son?