It's estimated that fewer than 40% of parents with minor children have even a basic will in place, and for obvious reasons. Planning for one's demise is unsettling, sometimes frustrating, and easily procrastinated given the general unlikelihood of premature death combined with the pressing needs of daily life. However, there are several reasons why parents of minor children need to be especially concerned about setting up an estate plan and should not rely on the routine machinations of the law in the event of disaster. Concern #1: who will care for your children?
If you have children under the age of 18, at a minimum you need to have a will that indicates who you would want to serve as guardian of those children in the event of your untimely demise. Absent such an instruction as to your preference, your children face a period of deep uncertainty as to who will take care of them—potentially even including some period of interim foster care--during what would already be a period of great trauma and grief. The adults who make up your surviving family members would have to decide amongst themselves who would be best suited to take on this responsibility, possibly leading to squabbles at best, and a court fight at worst. You might very likely also have the person you'd least want to take responsibility for your children as the only person willing to do so, while another person you might well prefer stays out of the matter. (Many of my clients express the opposite concern: that no one will step forward to take their kids! I think they are kidding.)
Single parents need to take special care as to this choice; widowed parents are clearly running a far greater risk that something could happen leaving their children with no living biological parent. In the event of divorced parents, a surviving biological parent would automatically assume custody absent some compelling reason such arrangement would not be appropriate; however, the deceased parent's wishes as to alternate guardian arrangements could affect visitation rights and other arrangements for surviving family members who wish to remain involved in the life of the child.