In reply to bleddynmawr:
I've got 4 children aged between 40 and 50. I still refer to them collectively as my kids. They don't mind in the slightest.
However as they all have now got their own children it's rare for me to use the collective noun as they are very rarely all there at the same time, and generally I introduce them to others as either my son or my daughter.
Post edited at 16:30