Gender-specific modes of addressing someone are uncommon, to my knowledge. "Dear teacher" includes both Lehrer and Lehrerinnen.
Was that the question... not sure.

You don't mean "political correctness" or "gender-neutral language" do you?

i.e. fireman -> firefighter
chairman -> chairperson

thank you for your postings

I'm aware of it that such a thing doesn't exist in English due to gender-neutral language so it is correspondingly diffucult to translate.

but instead of scraping this part of the text i thought about saying
"modes of adressing both genders" or just "adressing both genders"

how is that?

gender-neutral alternative

It's not true that such a thing doesn't exist in English. Gender-neutral language is also a problem. We just had to edit a text, where we had a long discussion whether we should write ...when XYZ has done XYZ then he/she has to..... or just to leave out the "/she" part.

So far, I haven't seen a good way of dealing with this that both makes a text readable and at the same time is fair to both genders.

@Björn:
the question was not how to address people in such a way, but what to call this form of address, i.e. the answer is simply gender-neutral