Do you ever give your adult children parenting advice?

I realize this is a very delicate area and tend to not do it but there are times when am biting my tongue. If you do ever, how is it received? Do you give it to your child and spouse or just to your child? Does it make a difference if you have a son or a daughter, i.e, are you more comfortable giving advice to a daughter than a daughter-in-law?

Your thoughts? My main philosophy has been to not give advice unless I really see something damaging to the child but there are little bits of wisdom I would love to pass on.