delivered the opinion of the Court.
The appellant, Abdiel Caban, challenges the constitutionality of § 111 of the New York Domestic Relations Law (Mc*382Kinney 1977), under which two of his natural children were adopted by their natural mother and stepfather without his consent. We find the statute to be unconstitutional, as the distinction it invariably makes between the rights of unmarried mothers and the rights of unmarried fathers has not been shown to be substantially related to an important state interest.
I
Abdiel Caban and appellee Maria Mohammed lived together in New York City from September 1968 until the end of 1973. During this time Caban and Mohammed represented themselves as being husband and wife, although they never legally married. Indeed, until 1974 Caban was married to another woman, from whom he was separated. While living with the appellant, Mohammed gave birth to two children: David Andrew Caban, born July 16, 1969, and Denise Caban, born March 12, 1971. Abdiel Caban was identified as the father on each child’s birth certificate, and lived with the children as their father until the end of 1973. Together with Mohammed, he contributed to the support of the family.
In December 1973, Mohammed took the two children and left the appellant to take up residence with appellee Kazin Mohammed, whom she married on January 30, 1974. For the next nine months, she took David and Denise each weekend to visit her mother, Delores Gonzales, who lived one floor above Caban. Because of his friendship with Gonzales, Caban was able to see the children each week when they came to visit their grandmother.
In September 1974, Gonzales left New York to take up residence in her native Puerto Rico. At the Mohammeds’ request, the grandmother took David and Denise with her. According to appellees, they planned to join the children in Puerto Rico as soon as they had saved enough money to start a business there. During the children’s stay with their grandmother, Mrs. Mohammed kept in touch with David and *383Denise by mail; Caban communicated with the children through his parents, who also resided in Puerto Rico. In November 1975, he went to Puerto Rico, where Gonzales willingly surrendered the children to Caban with the understanding that they would be returned after a few days. Caban, however, returned to New York with the children. When Mrs. Mohammed learned that the children were in Caban’s custody, she attempted to retrieve them with the aid of a police officer. After this attempt failed, the appellees instituted custody proceedings in the New York Family Court, which placed the children in the temporary custody of the Mohammeds and gave Caban and his new wife, Nina, visiting rights.
In January 1976, appellees filed a petition under § 110 of the New York Domestic Relations Law to adopt David and Denise.1 In March, the Cabans cross petitioned for adoption. After the Family Court stayed the custody suit pending the outcome of the adoption proceedings, a hearing was held on the petition and cross-petition before a Law Assistant to a New York Surrogate in Kings County, N. Y. At this hearing, both the Mohammeds and the Cabans were represented by counsel and were permitted to present and cross-examine witnesses.
The Surrogate granted the Mohammeds’ petition to adopt the children, thereby cutting off all of appellant’s parental *384rights and obligations.2 In his opinion, the Surrogate noted the limited right under New York law of unwed fathers in adoption proceedings: “Although a putative father’s consent to such an adoption is not a legal necessity, he is entitled to an opportunity to be heard in opposition to the proposed stepfather adoption.” Moreover, the court stated that the appellant was foreclosed from adopting David and Denise, as the natural mother had withheld her consent. Thus, the court considered the evidence presented by the Cabans only insofar as it reflected upon the Mohammeds’ qualifications as prospective parents. The Surrogate found them well qualified and granted their adoption petition.
The New York Supreme Court, Appellate Division, affirmed. It stated that appellant’s constitutional challenge to § 111 was foreclosed by the New York Court of Appeals’ decision in In re Malpica-Orsini, 36 N. Y. 2d 568, 331 N. E. 2d 486 (1975), appeal dism’d for want of substantial federal question sub nom. Orsini v. Blasi, 423 U. S. 1042 (1976). In re David Andrew C., 56 App. Div. 2d 627, 391 N. Y. S. 2d 846 (1977). The New York Court of Appeals dismissed the appeal in a *385memorandum decision based on In re Malpica-Orsini, supra. In re David A. C., 43 N. Y. 2d 708, 372 N. E. 2d 42 (1977).
On appeal to this Court, appellant presses two claims. First, he argues that the distinction drawn under New York law between the adoption rights of an unwed father and those of other parents violates the Equal Protection Clause of the Fourteenth Amendment. Second, appellant contends that this Court’s decision in Quilloin v. Walcott, 434 U. S. 246 (1978), recognized the due process right of natural fathers to maintain a parental relationship with their children absent a finding that they are unfit as parents.3
II
Section 111 of the N. Y. Dom. Rel. Law (McKinney 1977) provides in part that
“consent to adoption shall be required as follows: . . . (b) Of the parents or surviving parent, whether adult or infant, of a child born in wedlock; [and] (c) Of the mother, whether adult or infant, of a child bom out of wedlock. . .
The statute makes parental consent unnecessary, however, in certain cases, including those where the parent has abandoned or relinquished his of her rights in the child or has been adjudicated incompetent to care for the child.4 Absent one of *386these circumstances, an unwed mother has the authority under New York law to block the adoption of her child simply by withholding consent. The unwed father has no similar control *387over the fate of his child, even when his parental relationship is substantial — as in this case. He may prevent the termination of his parental rights only by showing that the best interests of the child would not permit the child’s adoption by the petitioning couple.
Despite the plain wording of the statute, appellees argue that unwed fathers are not treated differently under § 111 from other parents. According to appellees, the consent requirement of § 111 is merely a formal requirement, lacking in substance, as New York courts find consent to be unnecessary whenever the best interests of the child support the adoption. Because the best interests of the child always determine whether an adoption petition is granted in New York, appellees contend that all parents, including unwed fathers, are subject to the same standard.
Appellees’ interpretation of § 111 finds no support in New York case law. On the contrary, the New York Court of Appeals has stated unequivocally that the question whether consent is required is entirely separate from that of the best interests of the child.5 Indeed, the Surrogate’s decision in the present case, affirmed by the New York Court of Appeals, was *388based upon the assumption that there was a distinctive difference between the rights of Abdiel Caban, as the unwed father of David and Denise, and Maria Mohammed, as the unwed mother of the children: Adoption by Abdiel was held to be impermissible in the absence of Maria’s consent, whereas adoption by Maria could be prevented by Abdiel only if he could show that the Mohammeds’ adoption of the children would not be in the children’s best interests. Accordingly, it is clear that § 111 treats unmarried parents differently according to their sex.6
III
Gender-based distinctions “must serve important governmental objectives and must be substantially related to achievement of those objectives” in order to withstand judicial scrutiny under the Equal Protection Clause. Craig v. Boren, 429 U. S. 190, 197 (1976). See also Reed v. Reed, 404 U. S. 71 (1971). The question before us, therefore, is whether the distinction in § 111 between unmarried mothers and unmarried fathers bears a substantial relation to some important state interest. Appellees assert that the distinction is justified by a fundamental difference between maternal and paternal relations — that “a natural mother, absent special circumstances, bears a closer relationship with her child . . . than a father does.” Tr. of Oral Arg. 41.
*389Contrary to appellees’ argument and to the apparent presumption underlying § 111, maternal and paternal roles are not invariably different in importance. Even if unwed mothers as a class were closer than unwed fathers to their newborn infants, this generalization concerning parent-child relations would become less acceptable as a basis for legislative distinctions as the age of the child increased. The present case demonstrates that an unwed father may have a relationship with his children fully comparable to that of the mother. Appellant Caban, appellee Maria Mohammed, and their two children lived together as a natural family for several years. As members of this family, both mother and father participated in the care and support of their children.7 There is no reason to believe that the Caban children — aged 4 and 6 at the time of the adoption proceedings — had a relationship with their mother unrivaled by the affection and concern of their father. We reject, therefore, the claim that the broad, gender-based distinction of § 111 is required by any universal difference between maternal and paternal relations at every phase of a child’s development.
As an alternative justification for § 111, appellees argue that the distinction between unwed fathers and unwed mothers is substantially related to the State’s interest in promoting the adoption of illegitimate children. Although the legislative *390history of § 111 is sparse,8 in In re Malpica-Orsini, 36 N. Y. 2d 568, 331 N. E. 2d 486 (1975), the New York Court of Appeals identified as the legislature’s purpose in enacting § 111 the furthering of the interests of illegitimate children, for whom adoption often is the best course.9 The court concluded:
“To require the consent of fathers of children born out of wedlock ... , or even some of them, would have the overall effect of denying homes to the homeless and of depriving innocent children of the other blessings of adoption. The cruel and undeserved out-of-wedlock stigma would continue its visitations. At the very least, the worthy process of adoption would be severely impeded.” 36 N. Y. 2d, at 572, 331 N. E. 2d, at 489.
The court reasoned that people wishing tO' adopt a child born out of wedlock would be discouraged if the natural father could prevent the adoption by the mere withholding of his consent. Indeed, the court went so far as to suggest that “[m]arriages would be discouraged because of the reluctance of prospective husbands to involve themselves in a family sit*391uation where they might only be a foster parent and could not adopt the mother's offspring.” Id., at 573, 331 N. E. 2d, at 490. Finally, the court noted that if unwed fathers’ consent were required before adoption could take place, in many instances the adoption would have to be delayed or eliminated altogether, because of the unavailability of the natural father.10
The State’s interest in providing for the well-being of illegitimate children is an important one. We do not question that the best interests of such children often may require their adoption into new families who will give them the stability of a normal, two-parent home. Moreover, adoption will remove the stigma under which illegitimate children suffer. But the unquestioned right of the State to further these desirable ends by legislation is not in itself sufficient to justify the gender-based distinction of § 111. Rather, under the relevant cases applying the Equal Protection Clause it must be shown that the distinction is structured reasonably to further these ends. As we repeated in Reed v. Reed, 404 U. S., at 76, such a statutory “classification 'must be reasonable, not arbitrary, and must rest upon some ground of difference having a fair and substantial relation to the object of the legislation, so that all persons similarly circumstanced shall be treated alike.’ Royster Guano Co. v. Virginia, 253 U. S. 412, 415 (1920).”
We find that the distinction in § 111 between unmarried mothers and unmarried fathers, as illustrated by this case, does not bear a substantial relation to the State’s interest in providing adoptive homes for its illegitimate children. It may be that, given the opportunity, some unwed fathers would prevent the adoption of their illegitimate children. This impediment to adoption usually is the result of a natural *392parental interest shared by both genders alike; it is not a manifestation of any profound difference between the affection and concern of mothers and fathers for their children. Neither the State nor the appellees have argued that unwed fathers are more likely to object to the adoption of their children than are unwed mothers; nor is there any self-evident reason why as a class they would be.
The New York Court of Appeals in In re Malpica-Orsini, supra, suggested that the requiring of unmarried fathers’ consent for adoption would pose a strong impediment for adoption because often it is impossible to locate unwed fathers when adoption proceedings are brought, whereas mothers are more likely to remain with their children. Even if the special difficulties attendant upon locating and identifying unwed fathers at birth would justify a legislative distinction between mothers and fathers of newborns,11 these difficulties need not persist past infancy. When the adoption of an older child is sought, the State’s interest in proceeding with adoption cases can be protected by means that do not draw such an inflexible gender-based distinction as that made in § 111.12 In those cases where the father never has come forward to participate in the rearing of his child, nothing in the Equal Protection Clause precludes the State from withholding from him the privilege of vetoing the adoption of that child. Indeed, under the statute as it now stands the surrogate may proceed in the absence of consent when the parent whose consent otherwise would be required never has come forward or has abandoned the child.13 See, e. g., In re Orlando F., 40 N. Y. 2d 103, 351 *393N. E. 2d 711 (1976). But in cases such as this, where the father has established a substantial relationship with the child and has admitted his paternity,14 a State should have no difficulty in identifying the father even of children born out of wedlock.15 Thus, no showing has been made that the different treatment afforded unmarried fathers and unmarried mothers under § 111 bears a substantial relationship to the proclaimed interest of the State in promoting the adoption of illegitimate children.
*394In sum, we believe that § 111 is another example of “over-broad generalizations” in gender-based classifications. See Califano v. Goldfarb, 430 U. S. 199, 211 (1977); Stanton v. Stanton, 421 U. S. 7, 14-15.(1975). The effect of New York’s classification is to discriminate against unwed fathers even when their identity is known and they have manifested a significant paternal interest in the child. The facts of this case illustrate the harshness of classifying unwed fathers as being invariably less qualified and entitled than mothers to exercise a concerned judgment as to the fate of their children. Section 111 both excludes some loving fathers from full participation in the decision whether their children will be adopted and, at the same time, enables some alienated mothers arbitrarily to cut off the paternal rights of fathers. We conclude that this undifferentiated distinction between unwed mothers and unwed fathers, applicable in all circumstances where adoption of a child of theirs is at issue, does not bear a substantial relationship to the State’s asserted interests.16
The judgment of the New York Court of Appeals is
Reversed.
Section 110 of the N. Y. Dom. Rel. Law (McKinney 1977) provides in part:
“An adult or minor husband and his adult or minor wife together may adopt a child of either of them born in or out of wedlock and an adult or minor husband or an adult or minor wife may adopt such a child of the other spouse.”
Although a natural mother in New York has many parental rights without adopting her child, New York courts have held that § 110 provides for the adoption of an illegitimate child by his mother. See In re Anonymous Adoption, 177 Misc. 683, 31 N. Y. S. 2d 595 (Surr. Ct. 1941).
Section 117 of the N. Y. Dom. Rel. Law (McKinney 1977) provides, in part, that
“[a]fter the making of an order of adoption the natural parents of the adoptive child shall be relieved of all parental duties toward and of all responsibilities for and shall have no rights over such adoptive child or to his property by descent or succession, except as hereinafter stated.”
As an exception to this general rule, § 117 provides that “[w]hen a natural or adoptive parent, having lawful custody of a child, marries or remarries and consents that the stepfather or stepmother may adopt such child, such consent shall not relieve the parent so consenting of any parental duty toward such child nor shall such consent or the order of adoption affect the rights of such consenting spouse and such adoptive child to inherit from and through each other and the natural and adopted kindred of such consenting spouse.”
In addition, § 117 (2) provides that adoption shall not affect a child’s right to distribution of property under his natural parents’ will.
As the appellant was given due notice and was permitted to participate-as a party in the adoption proceedings, he does not contend that he was denied the procedural due process held to be requisite in Stanley v. Illinois, 405 U. S. 645 (1972).
At the time of the proceedings before the Surrogate, § 111, as amended by 1975 N. Y. Laws, chs. 246 and 704, provided:
“Subject to the limitations hereinafter set forth consent to adoption shall be required as follows:
“1. Of the adoptive child, if over fourteen years of age, unless the judge or surrogate in his discretion dispenses with such consent;
“2. Of the parents or surviving parent, whether adult or infant, of a child bom in wedlock;
*386“3. Of the mother, whether adult or infant, of a child born out of wedlock;
“4. Of any person or authorized agency having lawful custody of the adoptive child.
“The consent shall not be required of a parent who has abandoned the child or who has surrendered the child to an authorized agency for the purpose of adoption under the provisions of the social services law or of a parent for whose child a guardian has been appointed under the provisions of section three hundred eighty-four of the social services law or who has been deprived of civil rights or who is insane or who has been judicially declared incompetent or who is mentally retarded as defined by the mental hygiene law or who has been adjudged to be an habitual drunkard or who has been judicially deprived of the custody of the child on account of cruelty or neglect, or pursuant to a judicial finding that the child is a permanently neglected child as defined in section six hundred eleven of the family court act of the state of New York; except that notice of the proposed adoption shall be given in such manner as the judge or surrogate may direct and an opportunity to be heard thereon may be afforded to a parent who has been deprived of civil rights and to a parent if the judge or surrogate so orders. Notwithstanding any other provision of law, neither the notice of a proposed adoption nor any process in such proceeding shall be required to contain the name of the person or persons seeking to adopt the child. For the purposes of this section, evidence of insubstantial and infrequent contacts by a parent with his or her child shall not, of itself, be sufficient as a matter of law to preclude a finding that such parent has abandoned such child.
“Where the adoptive child is over the age of eighteen years the consents specified in subdivisions two and three of this section shall not be required, and the judge or surrogate in his discretion may direct that the consent specified in subdivision four of this section shall not be required if in his opinion the moral and temporal interests of the adoptive child will be promoted by the adoption and such consent cannot for any reason be obtained.
“An adoptive child who has once been lawfully adopted may be readopted directly from such child’s adoptive parents in the same manner as from its natural parents. In such case the consent of such natural parents shall not be required but the judge or surrogate in his discretion *387may require that notice be given to the natural parents in such manner as he may prescribe.”
See In re Corey L. v. Martin L., 45 N. Y. 2d 383, 391, 380 N. E. 2d 266, 270 (1978):
“Absent consent, the first focus here was on the issue of abandonment since neither decisional rule nor statute can bring the relationship to an end because someone else might rear the child in a more satisfactory fashion .... Abandonment, as it pertains to adoption, relates to such conduct on the part of a parent as evinces a purposeful ridding of parental obligations and the foregoing of parental rights — a withholding of interest, presence, affection, care and support. The best interests of the child, as such, is not an ingredient of that conduct and is not involved in this threshold question. While promotion of the best interests of the child is essential to ultimate approval of the adoption application, such interests cannot act as a substitute for a finding of abandonment.” (Citations omitted.)
The dissents speculate that the sex-based distinction of § 111 might not apply to those unwed fathers who obtain legal custody of their children. See post, at 395, and at 412-413, n. 23. But no New York court has so ruled. Indeed, one court has indicated that, at least with respect to legitimate children, the provision in § 111 (4) giving legal guardians a veto over the adoption of their wards applies only if the natural parents are dead. See In re Mendelsohn’s Adoption, 180 Misc. 147, 149, 39 N. Y. S. 2d 384, 386 (Surr. Ct. 1943). We should not overlook, therefore, the New York courts’ exclusive reliance upon § 111 (3) and instead speculate whether, if Caban had sought and obtained legal custody of his children, his legal rights would have been different under New York law.
In rejecting an unmarried father’s constitutional claim in Quilloin v. Walcott, 434 U. S. 246 (1978), we emphasized the importance of the appellant’s failure to act as a father toward his children, noting that he “has never exercised actual or legal custody over his child, and thus has never shouldered any significant responsibility with respect to the daily supervision, education, protection, or care of the child. Appellant does not complain of his exemption from these responsibilities and, indeed, he does not even now seek custody of his child.” Id., at 256.
In Quilloin we expressly reserved the question whether the Georgia statute similar to § 111 of the New York Domestic Relations Law unconstitutionally distinguished unwed parents according to their gender, as the claim was not properly presented. See 434 U. S., at 253 n. 13.
Consent of the unmarried father has never been required for adoption under New York law, although parental consent otherwise has been required at least since the late 19th century. See, e. g., 1896 N. Y. Laws, ch. 272. There are no legislative reports setting forth the reasons why the New York Legislature excepted unmarried fathers from the general requirement of parental consent for adoption.
In Orsini v. Blasi, 423 U. S. 1042 (1976), the Court dismissed an appeal from the New York Court of Appeals challenging the constitutionality of § 111 as applied to an unmarried father whose child had been ordered adopted by a New York Family Court. In dismissing the appeal, we indicated that a substantial federal question was lacking. This was a ruling on the merits, and therefore is entitled to precedential weight. See Hicks v. Miranda, 422 U. S. 332, 344 (1975). At the same time, however, our decision not to review fully the questions presented in Orsini v. Blasi is not entitled to the same deference given a ruling after briefing, argument, and a written opinion. See Edelman v. Jordan, 415 U. S. 651, 671 (1974). Insofar as our decision today is inconsistent with our dismissal in Orsini, we overrule our prior decision.
In his brief as amicus curiae, the New York Attorney General echoes the New York Court of Appeals’ exposition in In re Malpica-Orsini of the interests promoted by § Ill’s different treatment of unmarried fathers. See Brief for New York Attorney General as Amicus Curiae 16-20.
Because the question is not before us, we express no view whether such difficulties would justify a statute addressed particularly to newborn adoptions, setting forth more stringent requirements concerning the acknowledgment of paternity or a stricter definition of abandonment.
See Comment, The Emerging Constitutional Protection of the Putative Father’s Parental Rights, 70 Mich. L. Rev. 1581, 1590 (1972).
If the New York Court of Appeals is correct that unmarried fathers often desert their families (a view we need not question), then allowing *393those fathers who remain with their families a right to object to the termination of their parental rights will pose little threat to the State’s ability to order adoption in most cases. For we do not question a State’s right to do what New York has done in this portion of § 111: provide that fathers who have abandoned their children have no right to block adoption of those children.
We do not suggest, of course, that the provision of § 111 making parental consent unnecessary in cases of abandonment is the only constitutional mechanism available to New York for the protection of its interest in allowing the adoption of illegitimate children when their natural fathers are not available to be consulted. In reviewing the constitutionality of statutory classifications, “it is not the function of a court ‘to hypothesize independently on the desirability or feasibility of any possible alternative [s]’ to the statutory scheme formulated by [the State].” Lalli v. Lalli, 439 U. S. 259, 274 (1978) (quoting Mathews v. Lucas, 427 U. S. 495, 515 (1976)). We note some alternatives to the gender-based distinction of § 111 only to emphasize that the state interests asserted in support of the statutory classification could be protected through numerous other mechanisms more closely attuned to those interests.
In Quilloin v. Walcott, 434 U. S. 246 (1978), we noted the importance in eases of this kind of the relationship that in fact exists between the parent and child. See n. 7, supra.
States have a legitimate interest, of course, in providing that an unmarried father’s right to object to the adoption of a child will be conditioned upon his showing that it is in fact his child. Cf. Lalli v. Lalli, supra, at 268-269. Such is not, however, the import of the New York statute here. Although New York provides for actions in its Family Courts to establish paternity, see N. Y. Family Court Act §§ 511 to 571 (McKinney 1975 and Supp. 1978-1979), there is no provision allowing men who have been determined by the court to be the father of a child born out of wedlock to object to the adoption of their children under § 111.
Appellant also challenges the constitutionality of the distinction made in § 111 between married and unmarried fathers. As we have resolved that the sex-based distinction of § 111 violates the Equal Protection Clause, we need express no view as to the validity of this additional classification.
Finally, appellant argues that he was denied substantive due process when the New York courts terminated his parental rights without first finding him to be unfit to be a parent. See Stanley v. Illinois, 405 U. S. 645 (1972) (semble). Because we have ruled that the New York statute is unconstitutional under the Equal Protection Clause, we similarly express no view as to whether a State is constitutionally barred from ordering adoption in the absence of a determination that the parent whose rights are being terminated is unfit.