Oh so not having observed a claimed bias that is inherently unobservable

I'm not talking about inherently unobservable behavior: I'm talking about things like publicly telling female students that women can't be good engineers or scientists. I think public statements like that, made in front of an entire class, are very much observable. Don't you agree?

not having made this observation makes me a misogynist

I never said you were a misogynist. My working theory is that in conversation, women might be disinclined to share stories with you about how authority figures in their lives discouraged them from pursuing technical careers because you sound like the kind of person who is committed to the belief that sexism doesn't exist or is not significant. I mean, given the bizarre lengths you go to in order to defend this particular bigot, I can't imagine you'd be very sympathetic to such stories....

Perhaps my scientific wants mean that I require proof where others are willing to accept hearsay and anecdote.

Perhaps. Your scientific wants are certainly not requiring you to write intelligible english prose.

You seem confused so let me explain. I never suggested that the story I presented was representative of all teachers. In fact, I explicitly said the opposite of that. What I actually said was: it is false to claim that there does not exist a single person who has ever told young women that women can't do well in science and engineering. To disprove claims of that nature, all I need is one single anecdote. That's it. And that's what I presented.

Approaching your anecdotal evidence as a crime, as what you claim surely is

Huh? There was no crime here. Being an ignorant ass is not against the law.

one might ask what the motivation of the alleged offender was - why would it matter to a teacher what sex the student is.

Because he was a bigot? In general, I don't expect all people to behave rationally all the time, so the notion that some people will occasionally act like bigots doesn't really surprise me. Do you find it surprising?

Are you sure that the teacher didn't just dislike your [now] wife; you're not yourself biased?

I suppose it is possible. But if that were true, I would have expected him to say "even though you scored highest, you can't be captain because I don't like you". In any event, this theory is not consistent with the fact that long before this incident, the teacher claimed that women could not be good at science and engineering. The simplest explanation that fits all the data is that he really believes the statement he made about women being no good at science and engineering and that when confronted with evidence that this belief was false, he decided to deny reality and claim my wife was unqualified.

What did her parents say, or were they complicit?

Why would any of that matter? My point was that a real live female was discouraged from pursuing a technical career by a bigoted authority figure. Your comment seemed to suggest that such occurrences do not happen. Regardless of what her parents did, this incident proves that such occurrences do happen.

Don't schools in your country care about abuse of power?

Ha ha you're funny! No, they do not.

Did she bother to say "like Marie Curie, Ada Lovelace, Lise Meitner, ..." granted I can't think of too many examples in the upper-echelons but a clear proof that the teacher was wrong.

She made a number of points, but the instructor was not swayed. Which is as you would expect: bigotry is irrational. If you really believe that women are incapable of doing science or engineering, there is nothing that a female student can say that will change your mind.

Is it possible that the teacher was attempting to motivate her, this sort of thing does happen.

Look, I don't know why you're so desperately scrambling to defend a bigot, but it is really creepy. Telling a woman that women can't be good engineers does not motivate them. In general, lying to people is not a good way to motivate them. Telling a woman that despite her superior performance, she won't be permitted to exercise leadership, will not motivate her.

What school was it, who was the teacher?

Why do you want to know?