This case comes before us on an interlocutory transfer without ruling from the Superior Court (Hampsey, J.). See SUP. Ct. R. 9.
The record contains the following facts. The petitioner, Douglas Hoyt Nelson, and the respondent, Sylvia Horsley, began dating in 1992. They have one biological child, Nelson James Robert Horsley, born on June 29, 1993. The parties never married each other.
The parties ended their romantic relationship in November 1994. In December 1994, the respondent adopted a son, Kent Horsley. In December 1995, the parties’ romantic relationship resumed, and the petitioner moved in with the respondent. On September 30, 2000, the respondent adopted two children from Ukraine, Emma Horsley and Molly Horsley.
Contrary to the petitioner’s assertions, the respondent contends that she assumed all child care duties and was the sole financial support for the children until 1998, at which time the petitioner shared some of the child care responsibilities and allegedly provided minimal financial support for the children. The petitioner refused the respondent’s repeated requests that he adopt Kent. In addition, the respondent asserts that although the petitioner traveled to Ukraine to meet Emma and Molly, he stated unequivocally that he would not adopt them.
In July 2001, the respondent asked the petitioner to move out of her residence. He did so in September of that year. Although the petitioner was at first allowed to visit with Kent, the respondent soon terminated the visitation after Kent began to exhibit what the respondent describes as increasing fear and anxiety over his visits with the petitioner.
In October, the petitioner filed a petition for custody and support of the parties’ biological child, which he later amended to seek custody and support orders with respect to the respondent’s adopted children.
The trial court transferred the following questions for interlocutory appeal:
*547A. Whether the Superior Court has subject matter jurisdiction to grant an unrelated third party custodial rights to minor children he has not adopted by virtue of the in loco parentis and psychological parent doctrines.
B. Whether An Order Granting Custodial Rights To An Unrelated Third Party Over the Express Objection of the Minor Children’s Sole Parent Violates the Parent’s Rights Under the State and Federal Constitutions. N.H. CONST. Pt. I Art. 2; U.S. Const[.] Amend. Xiv.
We begin with the second transferred question.
We address the defendant’s State Constitutional claim first, citing federal law only to aid in our analysis. State v. Ball, 124 N.H. 226, 231-33 (1983). We have recognized that
[t]he family and the rights of parents over it are natural, essential, and inherent rights within the meaning of the New Hampshire Constitution. Because of their fundamental importance, great judicial deference has been accorded parental rights. They have been found to operate against the State, against third parties, and against the child.
Roberts v. Ward, 126 N.H. 388, 391 (1985) (citations, quotation and ellipses omitted). We have long recognized the right to raise and care for one’s children as a fundamental liberty interest protected by Part I, Article 2 of the State Constitution, Petition of Kerry IX, 144 N.H. 146, 149 (1999), and have extended such protection to both natural and adoptive parents. Cf. In re Bill F., 145 N.H. 267, 276 (2000). Similarly, United States Supreme Court precedent recognizes “that the Due Process Clause of the Fourteenth Amendment [to the Federal Constitution] protects the fundamental right of parents to make decisions concerning the care, custody, and control of their children.” Troxel v. Granville, 530 U.S. 57, 66 (2000) (plurality opinion).
As we have explained in the past, the best interests of the child guide all custody matters. Bodwell v. Brooks, 141 N.H. 508, 512 (1996). There is a presumption, however, that “fit parents act in the best interests of their children.” Troxel, 530 U.S. at 68 (plurality opinion). “[S]o long as a parent adequately cares for his or her children (i.e., is fit), there will normally be no reason for the State to inject itself into the private realm of the family to further question the ability of that parent to make the best decisions concerning the rearing of that parent’s children.” Id. at 68-69 (plurality opinion). This judicial reluctance to interfere with parental prerogatives *548derives, historically, from the notion that parents have a natural entitlement to the exclusive companionship, care, custody, and management of their children. Preston v. Mercieri, 133 N.H. 36, 40 (1990). In the context of a divorce, however, the superior court may interfere with parental rights to determine a child’s best interests as between two fit parents. See RSA 458:17 (Supp. 2002).
The State does have “a competing interest in the welfare of children within its jurisdiction, and may, as parens patriae, intervene in the family milieu if a child’s welfare is at stake.” Preston, 133 N.H. at 40. We have noted that “parental rights are not absolute, but are subordinate to the State’s parens patriae power, and must yield to the welfare of the child.” Id. Citing Preston, the petitioner argues that he is entitled to custody of the respondent’s adopted children, over her objection, so long as it is in the children’s best interests. Preston, however, is not instructive because it dealt with the subject of visitation, an act we have said constitutes a “far lesser intrusion, or assertion of control, than ... an award of custody and [which is] thus not nearly as invasive of parents’ rights.” Roberts, 126 N.H. at 393 (quotation omitted). Moreover, application of the best interests of the child standard in a custody dispute between a natural or adoptive parent and a nonparent would offend due process if the parent’s conduct towards the child has not been inconsistent with the parent’s constitutionally protected status. See Price v. Howard, 484 S.E.2d 528, 534 (N.C. 1997).
The constitutional rights of the natural or adoptive parent over his or her children are not easily set aside. Only in the most unusual and serious of cases may such fundamental rights be abrogated in favor of an unrelated third person. In fact, in In re Samantha L., 145 N.H. 408 (2000), we noted that “a natural or adoptive parent who has not been found to have abused or neglected his or her child may not be deprived of custody of the child” unless it is proven that the parent is unfit to exercise custody of the child. Id. at 414 (quotation omitted). The right of parents to raise their children without interference is a fundamental liberty interest deserving of the highest level of protection. See Preston, 133 N.H. at 40.
The petitioner argues, however, that the status of parent should be extended to cover all persons who have established a parental relationship with a child through the in loco parentis or psychological parent doctrines, affording them the same constitutional protections. We disagree.
The common law defines a person in loco parentis as “one who intentionally accepts the rights and duties of natural parenthood with respect to a child not his own.” In re Diana P., 120 N.H. 791, 795 (1980), cert. denied, 452 U.S. 964 (1981), overruled on other grounds by In re *549Craig T., 147 N.H. 739, 744-45 (2002); see also In re Shelby R., 148 N.H. 237,242 (2002) (stepparents who demonstrate a full commitment to raising and caring for their stepchildren are generally charged with the rights and duties attributed to natural parents). For example, we have held that a couple who stood in loco parentis to a child were “persons ... legally aggrieved,” Durivage v. Vincent, 102 N.H. 481, 486 (1960) (quotation omitted), by a probate court’s denial of their petition for continued custody of the child and that the in loco parentis relationship “gave rise to personal rights which entitled them to appeal from the dismissal of their petition,” id. We have also stated that a plaintiff standing in loco parentis was permitted to maintain an action for damages for personal injury suffered by a minor child, and that such a person was “entitled to all the rights of a parent” while the relationship existed. Whitaker v. Warren, 60 N.H. 20, 26 (1880). Finally, in Bodwell we held that a stepfather’s role as an in loco parentis stepparent entitled him to assert legal rights as an intervenor in a child custody proceeding. Bodwell, 141 N.H. at 513. Nevertheless, we have never expressly held that an unrelated third person standing in loco parentis has the same constitutionally protected rights to custody as a natural or adoptive parent, nor are we persuaded to do so here. To do so could elevate the rights of any unrelated third person who has spent considerable time caring for a child over the fundamental liberty interests of natural or adoptive parents.
Because we find the in loco parentis and psychological parent doctrines substantially similar, we will not conduct a separate analysis under the psychological parent doctrine.
Accordingly, we answer the second transferred question, to the extent it addresses the State Constitution, in the affirmative, and hold that it would violate the fit natural or adoptive parent’s State constitutional rights to grant custodial rights to an unrelated third person over the express objection of that parent. We note, however, that this decision does not affect stepparents, who under certain circumstances have been recognized as having the right to seek custody if it is in the best interests of the child. See Bodwell, 141 N.H. at 514.
Given our answer above, we need not address either the second transferred question to the extent that it raises issues under the Federal Constitution, or the first transferred question.
Remanded.
Brock, C.J., and Broderick and Duggan, JJ., concurred; Nadeau, J., dissented.