Taxpayer Question:Can I Claim My Grandchild As A Dependent?

The taxpayers have a 19 year old unmarried daughter who had a baby a few months ago.  She and her infant son are living with them while she attends college full-time and works a part-time job. They already know that they may claim their daughter as a dependent on their tax return, regardless of her income, because she is under the age of 24 and a full-time student.  They also realize that the daughter cannot claim her young son as a dependent on her own tax return because they are claiming  her as a dependent.  Their question is if they may claim their grandson on their own tax return.  My answer:  Yes, as long as the father is not in the picture and not eligible to claim the child as a dependent.  If the taxpayers are providing more than half of the support of their grandchild coupled with the fact that the baby is living with them, they may claim him as a dependent.