At a leaving do for a very attractive teacher at the school I teach at the boss said that she was always given the bottom set boys groups, because from the moment she walked into the room they would just go silent [here he did imression of them gawping at her] and then she could imress them with her teaching skills.
I felt a bit uncomfortable with the comment - but feel that that kind of remark is often accepted as a joke. I just think it reminded me of how often women are judged on their attractiveness first and foremost.
AIBU to find it incredibly crass to mention this in a leaving speech (and to imply that this is the reason for this particular staff member being given boys' groups).