BOO children is the plural of child so, since it is a plural noun rather than the plural of a noun, shouldn't it be before the s i.e. children's menu ?
I would suggest that the apostrophe only goes after an S if the S is already part of the plural noun (e.g. nations', dogs') and that if the plural noun does not end in S then 'S is appended.
But that is only what seems sensible to me, so doesn't count.
Thank you all so much for the answers - I thought it should be "Children's menu" & now I'm convinced by your helpful responses! This site is now in my "Favourites" list!
There was talk on the TV (or it might have been the radio) the other day about getting rid of apostrophes from our language altogether as they serve no useful function. Apparently this has already happened in America. I want them to stay! I don't want to be like America.
Lottie, if it goes, as it well might, it'll just be because people stop using it. I imagine texting will help it on its way - too much bother just for a signle squiggly little mark you can hardly see.