The issues in this case are whether the Court of Appeals erred in reversing the trial court’s order: (1) dismissing the adoption proceeding involving Daniel James Clark; and (2) holding that the adoption proceeding cannot proceed without the consent of the biological father of the child. We find no error or abuse of discretion in the trial court’s order dismissing the adoption petition without prejudice to its refiling and finding that Mr. Lampe’s consent was necessary before the adoption proceeding could continue. We, therefore, reverse the Court of Appeals which held to the contrary.
The undisputed facts of this case are both heart rending and unique. They concern the efforts of the biological father of Daniel James Clark to assert his paternal rights and responsibilities over a period of more than six years of litigation during which time his child has been tentatively placed in an adoptive home, apparently unaware of his father’s efforts to establish contact with him.
Daniel James Clark was born to Stephanie Ann Clark on 25 August 1983. Ms. Clark had been dating Christian Paul Lampe from October 1982 until April 1983. During this period they had sexual relations, and Ms. Clark told Mr. Lampe that she was using some form of contraceptive when she was in actuality not using *63any form of birth control. In April 1983, Ms. Clark told Mr. Lampe that she did not want to see him again. At that time she knew that she was pregnant, but she did not tell Mr. Lampe. Ms. Clark carried the baby to full term without anyone in her family or Mr. Lampe’s family ever being aware of the pregnancy.
After giving birth to the child, Ms. Clark contacted Family Services, Inc., which is a non-profit, child-placing agency, and told its representative that she wished to give the child up for adoption. On 31 August 1983, Ms. Clark executed and delivered to Family Services a “Parent’s Release, Surrender and Consent to Adoption” in which she gave up rights to the child and consented to his adoption. Ms. Clark did this without ever telling Mr. Lampe about the birth. Before releasing her rights to the child, she told Family Services that Mr. Lampe was the father of the child. The record indicates thát Family Services knew that the child’s father was unaware of Ms. Clark’s pregnancy or the birth of his child. During the pre-adoption interviews, Ms. Clark was evasive about Mr. Lampe’s whereabouts and later gave Family Services an incorrect telephone number for him.
Armed with the knowledge that the father’s name was Christian Paul Lampe and that he had at least recently lived in the Winston-Salem area, Family Services made only one unsuccessful attempt to contact Mr. Lampe by telephone. While the local telephone directory had two listings for “Lampe,” Family Services called only one of them. This number had been disconnected, and Family Services made no attempt to call the second number which was that of Mr. Lampe’s parents, the number and address which Mr. Lampe used as his permanent address while away at college. The record reflects that Family Services made no other attempt to contact Mr. Lampe prior to initiating a termination proceeding even though: (1) Mr. Lampe had a North Carolina driver’s license since 1982 listing his parents’ home address as his permanent address; (2) Mr. Lampe paid personal property taxes in Forsyth County listing his parents’ home address as his permanent address; and (3) Mr. Lampe was registered to vote in Forsyth County again listing his parents’ address as his permanent home address. Family Services did not consult any of these public records in an attempt to locate Mr. Lampe but instead relied on the incomplete and inaccurate information which Ms. Clark provided.
*64On 1 December 1983, Family Services filed a petition to terminate Mr. Lampe’s parental rights. This petition was based on N.C.G.S. § 7A-289.32(6) which sets out when parental rights of the father of a child born out of wedlock may be terminated. Claiming that it was unable to locate Mr. Lampe, Family Services requested a preliminary hearing pursuant to N.C.G.S. § 7A-289.26. On 8 December 1983, the trial judge concluded, “[t]he father of the above-named child, not having been served with notice due to his exact whereabouts being unknown, must be served with notice by publication.” A notice of service by publication was published in a local newspaper. An order terminating Mr. Lampe’s parental rights was issued on 18 January 1984. The child was then placed with the adoptive parents who filed a petition for adoption on 16 February 1984. With the petition for adoption, the adoptive parents filed a copy of the termination order rather than the affidavit required by N.C.G.S. § 48-13.
While it had told the trial judge during the termination proceeding that it was unable to locate Mr. Lampe, Family Services sent him a letter at his parents’ address on 27 March 1984, after the termination order was entered and after the adoption petition was filed. This letter asked Mr. Lampe to contact the agency in order to provide information about his background and family medical history. Upon receipt of this letter in early April, Mr. Lampe immediately called Family Services and found out for the first time that Ms. Clark had a child in August 1983, that she had given the child up for adoption, and that she had named him as the father of the child. On 2 May 1984, Mr. Lampe filed a motion to set aside the termination order on the grounds that service upon him by publication was invalid because Family Services failed to use due diligence in attempting to locate him. On 14 June 1984, the district court set aside the termination order issued 18 January 1984 on the grounds that Family Services did not exercise a diligent effort at the time of the preliminary hearing to locate Mr. Lampe. The Court of Appeals affirmed the district court’s order, and this Court denied discretionary review. In re Clark, 76 N.C. App. 83, 332 S.E.2d 196, disc. rev. denied, 314 N.C. 665, 335 S.E.2d 322 (1985).
After he filed the motion to set aside the termination order, Mr. Lampe, on 4 May 1984, filed a special proceeding to legitimate the child and, on 23 July 1984, filed a motion for a restraining order prohibiting the clerk of superior court from proceeding with *65the adoption proceedings. The restraining order was issued on 29 August 1984.
After this Court denied discretionary review of the Court of Appeals’ decision affirming the setting aside of the termination order, Family Services voluntarily dismissed the petition for the termination order and filed a motion on 24 October 1985 to dismiss the restraining order which had prevented the adoption from proceeding. This motion was granted on 12 December 1985, and the order dismissing the restraining order further instructed the clerk of superior court to cause notice to be issued and served on Mr. Lampe, pursuant to N.C.G.S. § 48-6(a)(3), to show cause as to why his consent to the adoption of the child was necessary or required. This notice was filed on 4 February 1986. Included with this notice was a copy of an affidavit by the Director of Family Services. The affidavit, dated 2 January 1986, stated that prior to the filing of the adoption petition on 16 February 1984, Mr. Lampe had taken none of the steps enumerated in N.C.G.S. § 48-6(a)(3) which would make his consent necessary. The affidavit made no reference to the legitimation proceeding instituted by Mr. Lampe on 4 May 1984.
The assistant clerk of the superior court held a hearing on this matter and allowed Mr. Lampe to offer evidence as to why his consent was necessary before the adoption could proceed. On 9 June 1986, the assistant clerk filed an order which, based on findings of fact and conclusions of law, ordered among other things:
1. The consent of Christian Paul Lampe to the adoption of Daniel James Clark by the adoptive parents is not and shall not be necessary nor required; and
2. The adoption proceeding for the adoption of Daniel James Clark shall proceed without the consent of Christian Paul Lanipe
Mr. Lampe gave notice of appeal from this order on 13 June 1986. A de novo hearing was begun in the superior court on 27 January 1988. The trial judge made findings of fact and conclusions of law and issued an order on 16 May 1988. This order provided:
1. That the adoption petition is hereby dismissed without prejudice as to its refiling.
2. That the consent of the biological father is necessary before the adoption of the minor child, Daniel James Clark, may continue.
*66Family Services and the adoptive parents appealed from this order to the Court of Appeals. The Court of Appeals reversed the order of the trial judge and remanded the case to the superior court. In re Adoption of Clark, 95 N.C. App. 1, 381 S.E.2d 835 (1989). Mr. Lampe appealed to this Court as a matter of right based on the dissenting opinion in the Court of Appeals.
In his dissenting opinion, Judge Cozort said:
The majority’s opinion has the effect of overturning this Court’s 1985 decision .... To allow the petitioners to go forward with the adoption, without the father’s consent, makes meaningless our opinion overturning the termination order. In effect, we would allow the petitioners to terminate the father’s rights through the adoption process.
Id. at 13, 381 S.E.2d at 841 (Cozort, J., dissenting).
In N.C.G.S. §§ 48-13 and 48-15 our statutes set out what is necessary for a valid adoption “proceeding” when the child is born out of wedlock. Section 48-15 provides a form to be used for the petition which must be filed. In addition to the filing of the petition, N.C.G.S. § 48-13 provides:
No reference shall be made in any petition, interlocutory decree, or final order of adoption to the marital status of the biological parents of the child sought to be adopted, to their fitness for the care and custody of such child, nor shall any reference be made therein to any child being born out of wedlock.
In the case of a child born out of wedlock and not legitimated prior to the time of the signing of the consent, an affidavit setting forth such facts sufficient to show that only the consent required under G.S. 48-6 is necessary shall be filed with the petition for adoption.
N.C.G.S. § 48-13 (1984) (emphasis added). Thus our statutes clearly provide that, in the case of a child born out of wedlock, both the petition set out in N.C.G.S. § 48-15 and an affidavit conforming to the requirements of N.C.G.S. § 48-13 must be filed before a valid adoption proceeding has been instituted.
In the present case, the evidence is undisputed that the petition for adoption was filed, but the termination order, rather than the affidavit required by statute, was filed with the petition. This termination order was invalid because the service by publication *67was void since due diligence was not used to determine Mr. Lampe’s address'. In re Clark, 76 N.C. App. at 87-88, 332 S.E.2d at 199-200. Therefore, there was no valid adoption proceeding begun on 16 February 1984 since only the petition was filed, and the petition by itself is not enough.
Family Services and the adoptive parents argue that the filing of the affidavit is a mere technicality and the failure to file the affidavit by itself is not enough to keep this from being a valid adoption proceeding. We disagree. The statute provides that the petition shall make no reference to the status of the biological parents when the child has been born out of wedlock. N.C.G.S. § 48-13 (1984). The statute then goes on to provide that the information about whether the parent’s consent is necessary must be included in an affidavit which shall be filed with the petition. Id. The purpose of the filing of this affidavit is to allow the clerk of superior court to determine whether the adoption proceeding is properly filed so as to meet the essential requirements of the adoption statutes. This affidavit provides the basis for the clerk to determine if the father is a necessary party to the proceeding. Therefore, failure to file this affidavit is not a mere technicality; it goes to the heart of a valid adoption proceeding.
Since this proceeding was not a valid adoption proceeding, Mr. Lampe’s parental rights have not been cut off by the provisions of N.C.G.S. § 48-6(a)(3). This statute provides:
In the case of a child born out of wedlock the consent of the putative father shall not be required unless prior to the filing of the adoption petition:
a. Paternity has been judicially established or acknowledged by affidavit which has been filed in a central registry maintained by the Department of Human Resources; provided, the court shall inquire of the Department of Human Resources as to whether such an affidavit has been so filed and shall incorporate into the case record the Department’s certified reply; or
b. The child has been legitimated either by marriage to the mother or in accordance with provisions of G.S. 49-10, a petition for legitimation has been filed; or
c. The putative father has provided substantial support or consistent care with respect to the child and mother. *68Determination under G.S. 48-6(a)(3) that the adoption may proceed without the putative father’s consent shall be made only after notice to him pursuant to G.S. 1A-1, Rule 4. This notice shall be titled in the biological name of the child.
N.C.G.S. § 48-6(a)(3) (1984). Mr. Lampe filed a special proceeding in the superior court on 4 May 1984 to legitimate the child. This legitimation proceeding was filed before a valid adoption proceeding was filed. Therefore, the provisions of N.C.G.S. § 48-6(a)(3) do not take effect to keep Mr. Lampe from being a necessary party to an adoption proceeding involving his son.
We thus come to the crucial question in this case: when a termination order, later held to be invalid for failure to use due diligence in ascertaining the putative father’s address, is filed with an adoption petition in lieu of the affidavit required by N.C.G.S. § 48-13, may a subsequently filed affidavit relate back to the original filing date of the petition so as to cut off the rights of a putative father who filed a legitimation petition pursuant to N.C.G.S. § 49-10 before the affidavit was filed? The trial judge, in effect, gave a negative answer to the question, and the Court of Appeals reversed.
The Court of Appeals concluded that Family Services and the adoptive parents should be allowed under Rule 15 of the Rules of Civil Procedure to amend the adoption petition by filing the necessary affidavit. In re Adoption of Clark, 95 N.C. App. at 10, 381 S.E.2d at 840. Rule 15(a) provides that leave to amend “shall be freely given when justice so requires,” N.C.G.S. § 1A-1, Rule 15(a) (1983), “unless some material prejudice to the other party is demonstrated.” Mauney v. Morris, 316 N.C. 67, 72, 340 S.E.2d 397, 400 (1982) (citing Mangum v. Surles, 281 N.C. 91, 187 S.E.2d 697 (1972)). The decision to permit or deny an amendment rests within the sound discretion of the trial judge and should not be disturbed on appeal absent a showing of an abuse of that discretion. Mauney v. Morris, 316 N.C. at 72, 340 S.E.2d at 400; Henry v. Deen, 310 N.C. 75, 310 S.E.2d 326 (1984).
Clearly, in this case where Mr. Lampe could lose his parental rights, and where he has taken action to avoid that very outcome by filing a petition for legitimation after he learned about the birth of his child, Mr. Lampe would be prejudiced by any attempt to relate a filing back to a time when he had no notice of this fact. Mr. Lampe took appropriate action to avoid losing his parental *69rights after he found out about the child, and allowing the affidavit to relate back to the time when he did not know about the child would materially prejudice him. Under these circumstances, the trial judge did not abuse his discretion in not treating the affidavit, submitted two years after the adoption petition, as having been filed with the adoption petition.
Mr. Lampe argued in his brief that his due process and equal protection rights are violated by these adoption statutes which could allow a biological father to lose parental rights to a child when he did not know he had a child. However, since Mr. Lampe’s consent is necessary for the adoption in this case to proceed, we need not address these constitutional issues.
For thei reasons stated herein, the decision of the Court of Appeals is reversed, and the order of the trial court is reinstated.
Reversed.