Middle school administrators couldn't decide whether a trans student should be sheltered with boys or girls during an active shooter drill, so they left her outside https://metroweekly.com/2018/10/trans-student-barred-from-shelter-during-virginia-schools-mass-shooter-drill/…
The one time my school separated by gender was when the county did their AIDS presentation. '85 or '86.
That was public. My church school separated gender if anyone sneezed.