In various posts over the years, I have mentioned that I do not like being addressed in writing or speaking as Mrs., Miss, or Ms. when I know for a fact that the person writing or speaking addresses male professors as Professor or Dr., or, in written cases, when the person writing addresses himself (it has always been a himself) as Professor or Dr. I am somewhat sensitive to these incidents because my husband is never addressed in professional situations as Mr., only Professor or Dr.
It's OK to use Mr./Ms. for professors as long as these terms are used the same for all. For example, there are certain academic ecosystems in which the titles Mr./Ms. are routinely used for faculty, including some highly regarded institutions of higher education and the Chronicle of Higher Education. In these cases, the use of Mr. and Ms. is applied equally for men and women and that's fine.
Otherwise, I don't really care how my undergraduate students address me in writing or speaking. Those who address me as Mrs. or even Miss FSP may be making a sexist assumption that I am a non-PhD instructor (and in doing so show that they haven't read the syllabus, attended the first day of class, and/or looked at the course webpage), or they may just be clueless. If they call me Mrs./Ms./Miss FSP, I say "Just call me F". In my non-academic life, kids in my daughter's generation call the parents of friends by their first names, so there is no sector of my life in which I am routinely called Mrs. or Ms. FSP by people who know me.
If a student sends me an email addressed to "Mrs. FSP", I reply as I normally would, and sign the email with my first name. My title and contact information are at the bottom of the email in a sig file, should this information be of interest.
In fact, all other things being equal, my preference is for students to call me by my first name. I don't consider this disrespectful; I find it convenient. If a student is for some reason not comfortable calling me by my first name, I don't insist, but in those cases they do have to call me Dr. or Professor FSP, as there is zero chance at my institution that they are calling their male professors "Mr.".
6 months ago