An article in the New York Times today touches on whether it's OK or not to draw from real-life relationships for literary material.
Is this even in question? Every writer draws from real-life experience to write fiction, whether consciously or not.
The real question is, how much do you take from real life and how closely do your fictional characters resemble their real-life counterparts. And what are your motives in portraying them? Some people you meet in life are so interesting it would be a crime not to portray them in fiction if you have the chance.
The writers in the Times article say, of course, draw from real life, but be careful and avoid the kids. I think of that admonition when considering Joseph Heller's Something Happened, which, having read his daughter's memoir, certainly seems to mirror the annoyance he felt in middle age having to deal with his (real) children's problems. Philip Roth's I Married a Communist is supposedly a "a barely disguised riposte at Roth's ex-wife, Claire Bloom" for portraying him unsympathetically in her memoir.
I suppose it matters most if the fictional characterization is unflattering or one that makes fun of a real-life person.
What's your opinion? Where do you draw the line on how closely your fictional characters resemble their real-world doppelgangers?