How should I address my two supervisors (one man, one woman) in an email?

Question

I am currently doing a PhD. My professor, which is my first supervisor, is a man. My second supervisor is a woman and works for my first supervisor. The etiquette and the courtesy, at least in my country, requires to greet the female first, e.g.:

Dear Dr. Female,
Dear Prof. Dr. Male,

This sounds wrong to me, since my professor is my main supervisor. Can I greet my professor first without violating etiquette?

My PhD position is located in Germany; my research field is mathematics and I write everything in English.

Answer 1

Hierarchy beats Gender in Germany

In a professional context in Germany, hierarchy beats gender, at least according to the Knigge, which is an etiquette guide of nontrivial influence. This goes as far as to be gender-blind. Only rank is important.

So you would address the highest ranking person first, in this case, your professor.

Answer 2

This may sound flippant but I’m being 100% serious:

You’re doing a PhD in STEM and addressing your supervisors. The customary form of address is “Hi” or, if you have a very formal relationship with your supervisors, “Hello”; not “Dear Prof. Dr. X” — even in the traditionally hierarchical German system.

Starting an email to your supervisor with “Dear Prof. Dr. X” is distinctly weird and risks coming across as off-putting. If you’re not on first-name terms with your supervisors, simply leave off the name entirely from the salutation (i.e. write just “Hello”, not “Hello Xavier”).

Answer 3

In addition to @PhilYardman's point (which is correct) you also need to consider how directly your email addresses whom. This beats both hierarchy and gender: the importance in the style link in @PhilYardman's answer is evaluated in the context of the email.

• The ones who are primarily addressed (To) come first and are always greeted.
  So, if you primarily write to your secondary supervisor and "only" keep your supervisor informed of this, the greeting starts with "Dear Dr. Second-Supervisor"

• Those who are only informed (CC):

  • I name them, but usually put that greeting into parentheses. This reminds everyone that more people are reading this email, while also signalling that the ones in parentesis are only notified.
  • It would also be acceptable to not include them in the greeting.

• If there are further people on BCC, they are not named (that would defeat the purpose of BCC), but you may use a generic greeting - depending on the context and content anywhere between "Dear all" and "Sehr geehrte Damen und Herren" [Dear Madam or Sir - but the German version is in plural], or a group address (Say, "Dear supervisors")

• I'd adapt the level of formality ("Sehr geehrter Herr Prof. Dr. med. mult. Supervisor" - "Sehr geehrter Herr Prof. Supervisor" - "Lieber Prof. Supervisor" - "Lieber Herr Supervisor" - "Lieber Vorname") to the customs at your institute and to the likes of your supervisors. This varies a lot between fields, institutes and people...
  "Prof. Dr." sounds too formal to me for the STEM fields I work with - but e.g. in the medical field it is AFAIK quite common (and there the position in the hospital would be attached as well "Chefarzt Dr. med.").

Answer 4

The etiquette and the courtesy, at least in my country, requires to greet the female first

This answer will be a little bit on the philosophical side (probably too much so for some people’s taste), but I’d like to suggest another way of thinking about the question. Instead of asking what is tantamount to “how can I best conform to what my society expects of me in email greetings?”, you can turn the dilemma around and ask “how can I help dismantle antiquated social norms that assign different genders to predetermined roles, and push society ever so slightly in the direction of being more rational and fair?” In other words, put the focus not on being the best follower, but on being the best leader. Granted, the particular social norm in question is a harmless one, but the point is that it’s part of a larger pattern of gender-aware (or outright sexist) norms which are not all harmless.

If you like the idea of looking at things that way, just write the greeting in the way that seems most logical to you based on the content of your email and your relationships with the two co-advisors.

Of course, the specific dilemma in your question is so trivial that it doesn’t really provide much of an opportunity to be a leader. Whatever you do in this specific situation, I doubt anyone will even notice it, let alone know to interpret your behavior as a conscious attempt at shifting social norms (although if they happen to ask you about it, you can certainly explain the thinking that went into your decision). But I’m mainly suggesting this as a mindset to adopt in similar situations that you may encounter in the future, some of which may be more consequential. In other words, the current situation can be used as a kind of training or practice opportunity to get into the habit of challenging stupid social norms — particularly in a low-stakes environment where no matter what you do, it’s almost certain that nothing bad will happen.

Answer 5

In a professional context, it is often acceptable and actually useful to address correspondents using their functional title. In this case I think it would certainly be acceptable to use

 Dear Supervisors,

It sidesteps the issue of order and immediately makes it clear in what capacity you address them. This would of course not be appropriate in the context, e.g., of a course that you are assisting with which may have nothing to do with them being your (research) supervisors.