Context
I am a woman and I sometimes post things online, on Stack Exchange for instance. Usually, my posts are very neutral and do not provide any hint of my gender.
It seems that most people assume that I am a man since they refer to me by writing "he". I don't take it personally and I don't feel offended at all. I'm glad enough people answer my questions!
That being said, I'd like to politely inform people who mistake me for a man that I am actually a woman. I don't want it to sound aggressive because I don't really mind and it doesn't change anything to the answer, nonetheless I think they ought to know in order, maybe, to realize that there are also women here.
Question
How do I let online people know I'm a woman when they're assuming I'm male, without being awkward? I'm not a native English speaker so I'm not even sure how to phrase it in a natural way (and to that extent, maybe I should have posted that question in the English Language and Usage SE site).
Additional details
Example
It is true that as a developer, I sometimes post on allegedly more masculine websites. Yet the last example I have is a question I wrote about my bathroom door that could not be closed properly (on Lifehacks site). Someone commented an answer that suggested a solution implying me drilling holes:
perhaps he lives in rented accommodation and can't modify?
Completely harmless, but I'm still considering informing nicely the user of their mistake.
How about changing my user profile?
Some people pointed out that I could fill my profile or indicate my gender through my avatar or username. Indeed that way people would be less inclined to assume I’m a man. Nonetheless, I feel that it would just bypass the problem: I’m bothered by the fact that there are approximately half of human beings who are female and that I still should state my gender online in order not to be mistaken for a man. Moreover, I prefer gender neutral answers whenever the gender is not relevant, and the best way to get them is to have a neutral profile.