Strictly, it should be female teachers, female students, male teachers, male students
but that can sound a bit too formal for colloquial speech.
I think you will find it is common to mix them :
but male teachers ( more so than 'men teachers')
Again, 'boy' and 'girl' are substituted for 'male' and 'female'
The plural is made my adding an' s' (and so is the possessive case.)
So - it would become 'boys students' which is a mouthful, and sounds as if we are talking about the possessive case to boot: the students of the boys = the boys' students.
So it is simplified colloquially to 'boy students'. Easy to say and gets the meaning across - 'students who are boys.'
I don't think that 'boy students' has much parlance in high schools today though. I would imagine that students would be designated and referred to as male students/female students.
(I think too there are social and cultural factors from the past determining some of this. British education at least has a tradition of keeping sex out of the classroom. We do not want to emphasize (or even mention!) maleness and femaleness, particularly when it is bad enough their hormones are raging. So well into high school, they are referred to in less 'sexual' terms as still innocent boys and girls, as if puberty hasn't really happened for them yet !)