Is it common for grandparents to act as parents?

One alternative family structure previously thought of as an extended family situation has changed to one form of primary care for children: grandparents. As of 2012, one in ten children living in the United States resides with a grandparent. In the past, living with a grandparent usually meant that an extended family living situation included one or more grandparents living with the child's parent(s). Since 2000, when the government started tracking data about grandparents acting as parents, the number of families headed by grandparents without a biological parent present has continued to grow. Teen pregnancies, drug abuse, and divorce have all contributed to this trend. In this alternative family structure, grandparents find themselves thrown into the role of primary caregiver at a time when they usually have finished raising their biological children. This often places a strain on the grandparent unit because of medical care and financial issues. This trend crosses all race and culture boundaries. In fact, as of 2011, 51% of all children being raised by grandparents were white, with African American and Hispanic races making up the next largest percentages.
Resource:
Tremblay, K.R. (2014). Colorado State University. Grandparents as parents. Retrieved June 28, 2015 from United States Census Bureau. (2012) Profile America Facts for Features.
Retrieved June 28, 2015 from http://www.victorianweb.org/authors/carroll/ratner1.html