In ASL class today the teacher was reviewing and expanding on our knowledge of family relationships* and so, on the board in stick figures were drawn of a nuclear family consisting of mother-father-girl-boy. Then to get to grand-relationships and in laws and step relations the boy and girl grew up.
Adult daughter fell in love with and married a single mother. No one raised an eyebrow. Adult son appears to have been straight, first marriage failed, second was, like his sister's only marriage, with a single mother (thus more opportunity for step-relations.)
At no point was the class interrupted by either the collapse of civilization or someone saying that marriage between two women would cause such. And it would have been easy to do such when the professor's back was turned because the professor is deaf.
And that's the upside of going to a dirty godless liberal university. It's possible for people who aren't heterosexual to show up as examples in classes entirely unrelated to sexuality and have no moral judgement attached. Or to put it another way, it's possible for non-heterosexual people to be treated as normal and unremarkable.
It wasn't a super special whiteboard episode, it was just one of the possible marriages that could introduce the students to the signs for step-relations and in-laws.
*So, basically, how to sign things like: fall in love, date, boyfriend, girlfriend, go steady, get married, wedding, married, father, mother, son, daughter, sibling, brother, sister, aunt, uncle, niece, nephew, grand[mother, father, parent, son, daughter, child]. Also [relation] in law and step-[relation].