The issue here is if a 1974 guilty plea by the defendant to a criminal charge of nonsupport of an illegitmate child, and an order to pay a lump sum plus medical expenses to the child’s mother for the child’s benefit, is a bar to a subsequent civil action by a county social services department for child support.
Because we find that the trial judge entered summary judgment for the wrong party, we reverse the judgment below. To understand our decision, a review of when this remedy should be used is helpful.
Summary judgment under G.S. 1A-1, Rule 56(c) is proper when there is “no genuine issue as to any material fact....” This remedy “does not authorize the court to decide an issue of fact. It authorizes the court to determine whether a genuine issue of fact exists.” Vassey v. Burch, 301 N.C. 68, 72, 269 S.E. 2d 137, 140 (1980) (emphasis in original). “[I]ts purpose is to eliminate formal trials where only questions of law are involved. . . . Where there is no genuine issue as to the facts, the presence of important or *434difficult questions of law is no barrier to the granting of summary judgment.” Kessing v. Mortgage Co., 278 N.C. 523, 534, 180 S.E. 2d 823, 830 (1971). See also, W. Shuford, N.C. Civil Practice and Procedure § 56-7 (2d ed. 1981).
I. Paternity Question
The plaintiff argues that the criminal action established that the defendant is the child’s father and should estop further litigation on that question. At the same time, it argues that it can still seek support, even though the criminal action required the defendant to pay a lump sum award.
The defendant contends, however, that the plaintiff is es-topped from recovering in this civil action on the same issues against him because of the lump sum payment resulting from the criminal judgment.
We first note that the 1974 criminal action determined implicitly that the defendant was the parent of the minor child. The order of judgment specifically states that the lump sum payment was being ordered pursuant to G.S. 49-7. That statute states in relevant part:
The court before which the matter may be brought shall determine whether or not the defendant is a parent of the child on whose behalf the proceeding is instituted. After this matter has been determined in the affirmative, the court shall proceed to determine the issue as to whether or not the defendant has neglected or refused to provide adequate support and maintain the child who is the subject of the proceeding. After this matter shall have been determined in the affirmative, the court shall fix by order ... a specific sum of money necessary for the support and maintenance of the particular child who is the object of the proceedings.
(Emphasis added.) An affirmative answer to the paternity question is an indispensable prerequisite to the defendant’s conviction under this statute. Tidwell v. Booker, 290 N.C. 98, 110, 225 S.E. 2d 816, 823 (1976).
G.S. 49-7 is a part of Article I of Chapter 49. Another portion of that article, G.S. 49-2, states: “Any parent who willfully neglects or who refuses to provide adequate support and maintain *435his or her illegitimate child shall be guilty of a misdemeanor. . . (Emphasis added.) G.S. 49-2 is a criminal statute. State v. Beasley, 57 N.C. App. 208, 290 S.E. 2d 730, disc. rev. denied, 306 N.C. 559, 294 S.E. 2d 225 (1982).
Thus, the outcome of the case sub judice depends on whether the implicit determination of paternity in a prosecution by the State under Article 1 of G.S. 49 when the defendant pled guilty should estop a county social services department from seeking a subsequent determination of paternity and an order to pay child support.
Although it could be argued that the criminal judgment might be entitled to res judicata effect in this action because the parties to the two suits were the same, ie., the State prosecuted the defendant in the criminal action and the State, through its subdivision Wilkes County, brought this action, it is unnecessary for us to make such a holding. Instead, we give collateral estoppel effect to the implicit determination of paternity in the criminal action.
Collateral estoppel should be applied to an issue that was involved, litigated, and judicially determined in the prior action and when the prior judgment was dependent upon determination of the issue. King v. Grindstaff, 284 N.C. 348, 358, 200 S.E. 2d 799, 806 (1973).
As stated above, the criminal judgment here was dependent on a determination of paternity, although it was not explicitly stated. The collateral estoppel effect of the paternity issue is not affected by the fact that the conviction was based on a guilty plea. See IB Moore’s Federal Practice 5 0.418[1] (2d ed. 1982); 18 C. Wright, Federal Practice and Procedure § 4474 (1981).
The defendant relies on Tidwell and Smith v. Burden, 31 N.C. App. 145, 228 S.E. 2d 662 (1976), for the proposition that he can relitigate the paternity issue here. But those cases are distinguishable in two important ways.
First, the defendants there pled not guilty, unlike here, where the defendant pled guilty. Second, the plaintiffs in the civil suits in Tidwell and Smith were the mothers, not a county, which is a subdivision of the State. These factual differences make Tidwell and Smith inapplicable in the case sub judice.
*436II. Past support paid by the plaintiff
After concluding that the prior determination of paternity should be given collateral estoppel effect, we now must decide if the defendant is liable to the plaintiff for past support.
G.S. 110-135 states in relevant part:
Acceptance of public assistance by or on behalf of a dependent child creates a debt, in the amount of public assistance paid, due and owing the State by the responsible parent or parents of the child. . . . [A]ny county within the State which has provided public assistance to or on behalf of a dependent child shall be entitled to share in any sum collected under this section. . . .
The defendant here is a “responsible parent” under G.S. 110-129(3).
By accepting the public assistance, the recipient is deemed to have assigned to the county who gave the assistance the right to any child support owed up to the amount of public assistance. The county is subrogated to the right of the person having custody to recover any payments ordered by the courts of this State. G.S. 110-137. See Cox v. Cox, 44 N.C. App. 339, 341, 260 S.E. 2d 812, 813 (1979).
Because the debt for assistance paid by Wilkes County did not arise until after the 1974 criminal judgment, the County is not estopped from seeking repayment of the child support that it paid to the mother. As a result, the defendant father should reimburse the plaintiff Wilkes County for the public assistance that it has rendered up until this point. The plaintiff is subrogated to the mother’s right to recover this amount under G.S. 110-137.
III. Future Child Support
Finally, the plaintiff in this action seeks an order that would require the defendant to pay future child support. The defendant argues that the prior criminal proceeding bars such a recovery. We disagree.
The criminal proceeding only disposed of the defendant’s willful nonsupport of the minor child until the judgment rendered in that 1974 action. He was ordered to pay certain sums of money *437as a condition of a prayer for judgment continued. But that judgment and any sums paid pursuant to it did not satisfy his continuing support obligation.
The plaintiff’s complaint sought to have the defendant declared to be the minor child’s father and a support order under Article 3 of G.S. 49. G.S. 49-15, which is a part of Article 3, states:
Upon and after the establishment of paternity of an illegitimate child pursuant to G.S. 49-14, the rights, duties, and obligations of the mother and the father so established, with regard to support and custody of the child, shall be the same, and may be deteremined and enforced in the same manner, as if the child were the legitimate child of such father and mother. (Emphasis added.)
An action separate from the one brought under Article 3 of G.S. 49 is not required. As Tidwell stated, “Clearly, this statute contemplates that such rights may be determined and enforced in the action brought pursuant to G.S. 49-14. . . .” 290 N.C. at 115, 225 S.E. 2d at 826.
G.S. 50-13.4(b) places the primary liability for the support of a legitimate minor child on both parents. Other circumstances may be considered, including the relative ability of the parties to pay. G.S. 5043.4(c). These sections should be considered here in determining the defendant’s liability for the support of the minor child. G.S. 49-15. See R. Lee, N.C. Family Law § 251 (4th ed. 1981).
Because no findings were made below about the child’s reasonable needs and the father’s ability to pay them, we remand for such findings.
IV. Summary judgment for the plaintiff
We note that G.S. 1A-1, Rule 56 provides for summary judgment in favor of the plaintiff in appropriate cases even when the motion was oral, as in this case.
In addition, G.S. 1A-1, Rule 56(d) allows for a partial summary judgment when there is no genuine issue as to a material fact on part of the issues. When this case is returned for a determination of the amount of the child’s reasonable needs and the defendant’s ability to pay them, the other issues on which we *438have entered summary judgment for the plaintiff are deemed established. See W. Shuford, supra, at § 56-10.
In summary, we hold that summary judgment was improperly entered for the defendant and should have been entered for the plaintiff. But we remand for a finding on the reasonable needs of the minor child and the ability of the defendant to pay them.
Reversed and remanded.
Judge BECTON concurs. Judge Phillips dissents.