It's entirely possible that there's never any point where "observed gender" is even implied and my mind just filled in some blanks when it talks about passing for human. To be honest I never gave it an ounce of thought before this whole conversation.
I think that's what happened. Your mind filled in the gaps and assumed Murderbot's gender.
I'm pretty sure it's never stated it looks like either a man or a woman. I mean, if it can pass for human it must like either or at least androgynous, but Martha Wells never tells us which.
Quite possible. To loop back to my first post, my point was I could have sworn there were at least strong implications at times that it was male-coded, although without gender. But perhaps it is just my own personal mandela effect.
What I do find interesting though is how many people chimed in here with a very strong sense of this detail but it was all a mix of responses! :)