Google Regina Calcaterra. She's an author, attorney and politician from Long Island, who grew up homeless and in foster care. Her mother had 5 kids, by 5 different men.
As a thirty something year old adult, she took the man she always heard (from her mother - she didn't know him growing up) was her father, to court, and won a Supreme Court case, compelling him to submit to a DNA test. He did turn out to be her father, but still had no interest in having a relationship with her. She did get to know some of her extended family though. She recently published a memoir about her childhood and her search for her father - Etched in Sand.
Personally, I thought it was somewhat selfish of her to force herself into the man's life like that (he was married, and from what was implied in the book, her father was dating her mother and his wife to be at the same time, unknown to either woman), and cause a lot of pain for his wife. His wife never knew he had a child outside of their marriage.
But apparently, in New York State at least, because of that Supreme Court case, an adult child can now compel a potential parent to take a DNA test. I know the OP is in a different state, though.