Most courts give great deference to the parents of children in child custody matters, and grandparents are awarded custody of their grandchildren only under limited circumstances.

For example, if both parents are unfit to have custody of their children, or if both parents are deceased, or if one parent is deceased and the other is in prison, grandparents may petition the court for custody of their grandchildren.

And grandparent visitation rights vary from state to state, and are often conditioned on certain circumstances, such as when the child’s parents are divorced, separated, or deceased.

In Massachusetts, the law recognizes the primacy of parents' rights in child custody matters. Grandparents may be awarded custody of their grandchildren under certain limited circumstances, such as when both parents are deemed unfit, both have passed away, or one is deceased and the other is incarcerated. However, these situations are exceptional, and the grandparents must demonstrate that such an arrangement is in the best interest of the child. Regarding visitation, Massachusetts law allows grandparents to petition for visitation rights under specific conditions, such as when the parents are divorced or separated, or if one or both parents are deceased. The court will consider the best interest of the child when deciding on grandparent visitation rights. It's important to note that these rights are not automatic and the grandparents must file a petition in court to obtain custody or visitation rights.