In Matter of Sheila G., 61 N.Y.2d 368, the Court held that the diligent efforts requirement is a condition precedent which the agency must prove before the court may even consider whether the parent has met his or her duty to maintain contact with and plan for the future of the child. The agency's obligation was described by the Court as follows: ... To enable a child to return to his or her family, an agency must have the capability to diagnose the problems of the parent and of the child; access to a host of concrete supportive and rehabilitative services; cooperation with community treatment programs (such as health, alcohol, and drug treatment); and a casework staff that can motivate the parents to avail themselves of services .... lower courts have recognized that an agency is in a superior position to the parent with respect to the planning factor. The parties are by no means dealing on an equal basis. The parent is by definition saddled with problems: economic, physical, sociological, psychiatric, or any combination thereof. The agency, in contrast, is vested with expertise, experience, capital, manpower and prestige. Agency efforts correlative to their superiority are obligatory.... The corollary to the agency's dominant position is that indifference by the agency may greatly serve to impede a parent's attempts at reunification.... Of course, transcending the practical reasons for providing a threshold requirement that an agency exercise diligent efforts toward reuniting parent and child is the strong public policy that before the State may terminate parents' rights it must first attempt to strengthen familial ties. [Matter of Sheila G., supra, 61 N.Y.2d at 381-383]