i don't think it would ever be harmful for my son to see me naked but i think we'll both feel uncomfortable with it when he's starting puberty and seeing women as sexual.
actually, he'll most likely decide to stop before that. kids just reach an age where they shut off that way.
but up until that point, if he wants to chat to me in the bath then i'm ok with that.

my kids see images of nudity every day...i paint nudes. i own books with nudes. they're imune to nudity. i like it that way. better than learning from porn.