I think the right thing to do is have an adult section of the library. Like it or not we do have free speech etc. which includes porn. I wouldn't want my children to be able to view it, but I'm not sure how to draw a line between what should/not be in a library.

I would also put some of the photography and art books many of which have nudes in the adult section of the library, with Lady Chatterly type of material as well.