In Lehr v. Robertson, 463 U.S. 248 (1983), the Court held that a putative father who had never established a substantial relationship with his child was not entitled to notice of adoption proceedings as a matter of due process. Id. at 265. The dissenting opinion in Lehr reveals that the biological father in that case had aggressively pursued a relationship with the child, but had been thwarted by the child's mother. Lehr, 463 U.S. at 268-69 (WHITE, J., dissenting). Nevertheless, the Court held that the putative father's lack of any substantial relationship with the child weighed against recognizing a constitutional right to notice and hearing. The Court observed that the significance of the biological connection is that it offers the natural father an opportunity that no other male possesses to develop a relationship with his offspring. Where, however, the child is born into an extant marital family, the natural father's unique opportunity conflicts with the similarly unique opportunity of the husband of the marriage to parent the child. Michael H. v. Gerald D., 491 U.S. 110 (1989). In such instances, the United States Supreme Court has affirmatively held that it is not unconstitutional for the husband of the marriage to be given categorical preference over the natural father. Id. Furthermore, the United States Supreme Court has found that the relationship of love and duty in a recognized family unit is an interest in liberty entitled to constitutional protection. Lehr v. Robertson, 463 U.S. at 258. While the court has recognized that each married parent after divorce has some substantive due process right to maintain his or her parental relationship, the court has not extended such a right to every unwed parent. Id. at 260. In fact, the court has determined that parental rights do not spring full-blown from the biological connection between parent and child, but that they require more enduring relationships. Id. In Lehr v. Robertson, the United States Supreme Court found New York's paternity registry an appropriate means of accommodating and protecting the existing, yet undeveloped rights of putative fathers. The Court stated, "Since the New York statutes adequately protected the putative father's inchoate interest in establishing a relationship with the child, we find no merit in the claim that his constitutional rights were offended because the family court strictly complied with the notice provisions of the statute." Id. at 265. In Lehr the Court explained: The difference between the developed parent-child relationship that was implicated in Stanley v. Illinois, 405 U. S. 645 (1972), and Caban v. Mohammed, 441 U. S. 380 (1979), and the potential relationship involved in Quilloin v. Walcott, 434 U.S. 246, (1978) and this case, is both clear and significant. When an unwed father demonstrates a full commitment to the responsibilities of parenthood by "coming forward to participate in the rearing of his child," his interest in personal contact with his child acquires substantial protection under the due process clause. At that point it may be said that he "acts as a father toward his children." But the mere existence of a biological link does not merit equivalent constitutional protection. . . . "The importance of the familial relationship, to the individuals involved and to the society, stems from the emotional attachments that derive from the intimacy of daily association, and from the role it plays in 'promoting a way of life' through the instruction of children as well as from the fact of blood relationship."