I also agree with Dimcl.I must disagree with PidginBoy. "Born into" and "Born to" a poor family are the best options. "Born in" isn't usually used in this way. He wasn't "born in" a family, he was "born into" or "born to" a poor family.
Although I see examples of "born in a(n) [adjective] family" on the Internet via Google, it strikes me as odd. It seems much more usual to me to say "born into a(n) [adjective] family" as in: Born into a farm family. Born into an artistic family. Born into a Catholic family."Born into a farm family, I do not have a good study environment."
Is "born into" in the setence right? or should it be replaced by