Couldn't it be "children"? When "filios" are mixed gender (filiī + filiae)?
I agree, "children" should be accepted.
But in this particular case, the word used for children would be pueri -orum, or liberi -orum. However, I see your point. Maybe I'll do some more research into it.
Just to see what would happen, I tried "We teach many children." It was accepted (31 May 2020).
Interestingly, in portuguese we have different words for each gender:
I don't know how it works in Latin, but using the same context, 'filias' are also 'mixed gender'?
No, using feminine forms is strictly for all female groups, just like Portuguese.
Filios is masculine
What do you teach?