In our family, we don’t make our children hug or kiss other family members….not even grandparents. We do this to reinforce in our children that their bodies are their own….and no matter who it is…. adult/relative/friend….cannot make them do something with their body that they are uncomfortable with. What we tell them is that if they don’t want to hug or give a kiss, then to politely extend a hand for a handshake…though not even that is mandatory. Family members must understand that it is for the well being of the child that they have complete control over their physical affections. When we first decided this, both sets of grandparents weren’t happy…but completely understood and were supportive. It’s sad, but necessary in this day and age…..even among relatives. If I were you, I’d simply explain to the grandparents that you are not forcing your children to give physical affections unless the child wants to….to reinforce in them that only they have control over who they give hugs/kisses to. In the beginning, they’ll use it to get a rise out of the grandparents…LOL. But if the grandparent acts in agreement and understanding, it will be shortlived and the affections will come freely and because the child wants to….not because they have to. And isn’t it nicer to receive affection when you know its from someone who WANTS to give it? Well, I hope this helps.