when do we use "born of" and when "born to"?? is it ok to say that "she was born of poor parents"???

Answer 1

It's okay, but only just.
The only use I can think of where "of" is preferred to "to" in this context is: "Man, who is born of woman ..."
Otherwise, stick to "born to".

Answer 2

"Of" refers to people, "to" refers to conditions.

"She was born of poor parents."
"She was born to (or into) poverty."

However, this is a very old expression, no longer commonly used in English.