[Devora]

I think you handled it well.

It's a legitimate question and a serious issue that all of us need to deal with. Yet, it's not something to be discussing in front of children.

I think some kind of, "That is a very serious issue. However, we have no reason to believe there are any concerns with our son's adoption." is an appropriate response to the issue. With some people you might want to have an in-depth discussion about why you don't have any concerns. For other people an answer like this suffices.

As for talking in front of the children, I think it's good that you addressed it. Personally, I would have addressed it with the teacher rather than the director. Although it would be an awkward conversation in the moment, it is appropriate to address it with the teacher first. I'm not criticizing your decision to go to the director first -- just be aware that it could come across to the teacher as very heavy handed as going to a director is usually done when "disciplinary action" is warranted. This needed to be addressed, but it's more a matter of education/awareness than disciplinary action that would go in an employee file. She might feel very uncomfortable around you for a while, walking on pins and needles. So you might want to make an extra effort to be friendly to her the next time you see her.