In French we have a similar problem but sometimes you can work around it by using "la personne" (the person) and then use the feminine for the rest of the sentence. It's convenient were you're talking about an hypothetical people, of course it doesn't work if you're talking about a concrete person whose gender you want to obfuscate. Certainly there's something similar in German?
The historically "correct" way to do it in English was just to default to masculine unless the person in question was known to be a woman. (Or unless the person was in a role that you just assumed was a woman, like a secretary.)
Which is one of the problems. You're using the third person pronoun to make assumptions about genders for some role. (And beyond that, you're assuming binary gender identities.)
>The earliest known explicit recommendation by a grammarian to use the generic he rather than they in formal English is Ann Fisher's mid-18th century A New Grammar[...]
Meanwhile gender-neutral singular "they" has been used by some authors for much longer:
>"Eche on in þer craft ys wijs." ("Each one in their craft is wise.") — Wycliffe's Bible, Ecclus. 38.35 (1382)
By correct, in this context, I mostly meant English (especially American English) style guides and similar that were published over a number of decades prior to maybe ten years or so ago. I'm sure there are lots of individual examples that don't follow that timeline though.
After people started to become more generally sensitive to gender role assumptions and language that reinforced those assumptions, I can recall lots of examples of "he/she" constructions and/or writing examples in a way that you had both a male engineer and a female engineer.
The preference for using singular they in part because it doesn't still rely on binary pronouns is relatively recent in my personal experience--at least in formal writing.
