I am probably giving my age, but so what! In the 1960s there was a move for women to use the title of "Ms." pronounced "mz." It is based on the fact that "Mr." does not tell whether or not a man is married. However, the titles of "Mrs." and "Miss" do tell whether or not a woman is married. But why should women have to let that be known? Afterall, men do not! Let's show equality in this idea of using titles! Therefore, to be equal and politically correct, we should all use Ms. for women.
And for another note: Prior to the correct title of "Ms." I was always taught in school that if a woman is married and her husband is living, she would use his name. Example: Mrs. John Smith. If he was deceased or if she was divorced, then she could use Mrs. Sue Smith. Of course this is now thought of as antiquated thinking.
To sum it up, remember that a woman does not need to be married to gain respect nor does she have to show whether or not she is married in her title. Everyone should use "Ms." when addressing a woman.
Woman are EQUAL!