This is the relevant text:

> 3. Classroom instruction by school personnel or third parties on sexual orientation or gender identity may not occur in kindergarten through grade 3…

I read this to prohibit discussion of sexual attraction with kids third grade and under. I don’t read this to prohibit incidental mention of someone’s same-sex spouse.

In practice, there is no problem if a teacher shows video incidentally including a straight couple. If it contains a gay couple, however, suddenly that could count as "classroom instruction" of sexual orientation. The teachers are left with the unenviable position of interpreting a vague law, resulting in it being safest to exclusively show kids straight couples.