The California Supreme Court has discussed substantive due process rights in the juvenile dependency context as follows: "The federal and state Constitutions guarantee that no state shall deprive any person of life, liberty or property without due process of law. A parent's interest in the companionship, care, custody and management of his children is a compelling one, ranked among the most basic of civil rights. Likewise, natural children have a fundamental independent interest in belonging to a family unit , and they have compelling rights to be protected from abuse and neglect and to have a placement that is stable, permanent, and that allows the caretaker to make a full emotional commitment to the child. The interests of the parent and the child, therefore, must be balanced. Substantive due process prohibits governmental interference with a person's fundamental right to life, liberty or property by unreasonable or arbitrary legislation. In substantive due process law, deprivation of a right is supportable only if the conduct from which the deprivation flows is prescribed by reasonable legislation that is reasonably applied; that is, the law must have a reasonable and substantial relation to the object sought to be attained." (In re Marilyn H. (1993) 5 Cal.4th 295.) The high court continued: "The objective of the dependency scheme is to protect abused or neglected children and those at substantial risk thereof and to provide permanent, stable homes if those children cannot be returned home within a prescribed period of time. Although a parent's interest in the care, custody and companionship of a child is a liberty interest that may not be interfered with in the absence of a compelling state interest, the welfare of a child is a compelling state interest that a state has not only a right, but a duty, to protect." (In re Marilyn H., supra, 5 Cal.4th at p. 307.) In Daria D. v. Superior Court (1998) 61 Cal.App.4th 606, the Court rejected a substantive due process challenge to sections 361.5, subdivision (a)(2), and 366.21, subdivision (e), which allow the juvenile court at the six-month review hearing to terminate services and schedule a selection and implementation hearing under section 366.26 if the minor is under three years of age on the initial removal date. These statutes were properly applied in this case. It is well established that the primary purpose of the dependency system is to provide for the child's welfare and best interests. (See e.g., In re Kerry O. (1989) 210 Cal. App. 3d 326, 333, 258 Cal. Rptr. 448.) The protection of children is a compelling state interest. (In re Marilyn H., supra, 5 Cal.4th at p. 307.) The purpose of the six-month provisions is to allow the courts to better meet the needs of young children "'in cases with a poor prognosis for family reunification.'" (Daria D., supra, 61 Cal.App.4th at p. 611.) As the Court noted: "It is critical to secure stable placement for a dependent child as soon as possible, consistent with the parents' rights. Conversely, a child's need for permanency and stability cannot be delayed for an extended time without significant detriment." (Ibid.)