Censorship

As a teacher and a blogger, I feel a lot of responsibility when I recommend books, especially to kids and parents. Lately I have been looking at books I'd like to add to my son's elementary school library. It's a big responsibility.
Ultimately I believe it is the parents' responsibility to know what their child is reading. But no one can read everything, so parents count on resources like librarians, Amazon review, friends, etc. to help them.
Recently I read a new middle grade novel by a favorite and popular author. The sort of author whose books many parents - and schools - would buy without reading first. The book had a swear word in it several times. Because of that, I have found myself wrestling with questions of censorship.
*Can I recommend the book to family, friends and, more importantly, students in elementary school with that language?
I think I can recommend it to adults, but with the caveat that there is one swearword in the book a few times - let the parents decide if they are okay with that or not.
*While our small school library can't possibly house every book, is it okay to exclude a book because the language doesn't fit the school's Christian foundation?
Yes, because the language does not honor the school's mission. 
*If the book comes with our materials for book fair this fall, will I put it out on display?
This is a much trickier question. If I didn't know about the language, I would definitely have put it out. But I do know. I will yield to the wisdom of my building principal, but my instinct is to hold the book out, but sell it to families who request it and acknowledge that they are aware of the language and are choosing to buy it.

The bigger question I wrestle with, as a professional, is where my line of responsibility falls when it comes to making age-appropriate material available to students in a Christian school context, realizing that the parents are ultimately responsible for setting the boundaries for their own household about what is appropriate reading material?

Any thoughts? How do you define "censorship?"