Growling

Question
My Maltese dog is six months old. he sometimes growls at my 9 yr old and 12 yr old grandchildren. They seem to be playing normal with him. Why would he growl.

Answer
He's probably growling out of fear, or he simply wants them to stop.  The good news is that he growls and warns, rather than biting.  

The way to protect your grandchildren is to protect your dog.  Don't let them play "normal" if the DOG thinks it's abnormal.  Separate them if the pup is growling, or the kids are pestering.

If a dog has not been well socialized to kids, he may not like them all that much, or may be fearful of them - the critical socialization period when you would have wanted the puppy to be exposed to children was between age 8-12 weeks.  

Also, some pups view kids the way they would other puppies, as playmates, so might play roughly with them, as with another dog.  

Try to take into consideration your pup's body language to decide if he is fearful or anxious about the kids: http://www.pawsacrossamerica.com/interpret.html
http://www.petplace.com/dogs/what-is-your-dog-saying-a-key-to-canine-body-langua...

Even though you are the grandparent, I'd advise you to read:
http://www.amazon.com/Raising-Puppies-Kids-Together-Parents/dp/0793805686

The one thing not to do --- don't scold the pup for growling.  If he can't warn them for fear of reprisal, the next step is to just go ahead and bite.  Instead, remove the kids and let things calm down.  Hopefully, use the quiet time to read Pia's book:-))