                         Nebraska Advance Sheets
	                           IN RE INTEREST OF KODI L.	35
	                                Cite as 287 Neb. 35

    In   re I nterest of  Kodi L., a child under 18 years                   of age.
                      State of Nebraska, appellee, v.
                          Michael L., appellant.
                                    ___ N.W.2d ___

                      Filed December 13, 2013.      No. S-13-242.

 1.	 Juvenile Courts: Appeal and Error. An appellate court reviews juvenile cases
      de novo on the record and reaches its conclusions independently of the juvenile
      court’s findings.
 2.	 Paternity. The proper legal effect of a signed, unchallenged acknowledgment of
      paternity is a finding that the individual who signed as the father is in fact the
      legal father.
  3.	 ____. An acknowledgment of paternity can be challenged on the basis of fraud,
      duress, or material mistake of fact.
 4.	 Appeal and Error. In order to be considered by an appellate court, an alleged
      error must be both specifically assigned and specifically argued in the brief of the
      party asserting the error.
  5.	 ____. Errors assigned but not argued will not be addressed on appeal.
  6.	 ____. An issue not presented to or passed on by the trial court is not appropriate
      for consideration on appeal.

  Appeal from the County Court for Madison County: Ross A.
Stoffer, Judge. Affirmed.
  Joel E. Carlson, of Stratton, DeLay, Doele, Carlson &
Buettner, P.C., L.L.O., for appellant.
  Gail E. Collins, Deputy Madison County Attorney, for
appellee.
  Bradley C. Easland, of Morland, Easland & Lohrberg, P.C.,
guardian ad litem.
  Wright, Connolly, Stephan, McCormack, Miller-Lerman,
and Cassel, JJ.
    Wright, J.
                     NATURE OF CASE
   Michael L. appeals his exclusion and dismissal from the
juvenile proceedings involving Kodi L. The juvenile court dis-
missed Michael because it found that the acknowledgment of
paternity signed by him was fraudulent. Although Michael was
not Kodi’s biological father, he was named as Kodi’s father
   Nebraska Advance Sheets
36	287 NEBRASKA REPORTS



in the juvenile proceedings based upon the acknowledgment
of paternity.
   Under Neb. Rev. Stat. § 43-1409 (Reissue 2008), a notarized
acknowledgment of paternity creates a rebuttable presumption
of paternity that can be challenged only on the basis of fraud,
duress, or material mistake of fact. In the instant case, the
juvenile court found that the acknowledgment of paternity was
fraudulent, because Michael knew when he signed it that he
was not Kodi’s biological father. Therefore, the presumption of
paternity was rebutted, and the court dismissed Michael from
the proceedings. We affirm.

                    SCOPE OF REVIEW
   [1] We review juvenile cases de novo on the record and
reach our conclusions independently of the juvenile court’s
findings. In re Interest of Edward B., 285 Neb. 556, 827
N.W.2d 805 (2013).

                             FACTS
   Shawntel H. gave birth to Kodi in August 2012. Shortly
after Kodi’s birth, Shawntel and Michael signed a sworn
acknowledgment of paternity naming Michael as Kodi’s bio-
logical father before a notary public. When they executed the
acknowledgment of paternity, both Shawntel and Michael were
aware that Michael was not Kodi’s biological father. Despite
this fact, they requested that the birth certificate name Michael
as the father and that Kodi take Michael’s last name. In the
months following Kodi’s birth, Michael lived with Shawntel
and Kodi in an apartment.
   On December 5, 2012, Kodi was removed from the home
based on Shawntel’s use and sale of methamphetamine. The
State subsequently filed an amended juvenile petition alleging
that Kodi was a child within Neb. Rev. Stat. § 43-247(3)(a)
(Reissue 2008). Shawntel admitted the allegations, and the
county court for Madison County, sitting as a juvenile court,
granted the petition for adjudication. It ordered that Kodi be
placed in the custody of the Department of Health and Human
Services. In the amended petition, Michael was identified as
Kodi’s father.
                  Nebraska Advance Sheets
	                   IN RE INTEREST OF KODI L.	37
	                        Cite as 287 Neb. 35

    On February 15, 2013, Kodi’s guardian ad litem moved to
exclude Michael from the juvenile proceedings, challenging
on the basis of fraud the acknowledgment of paternity signed
by Michael. The guardian ad litem alleged that the acknowl-
edgment was fraudulent because Shawntel and Michael signed
it despite knowing that Michael was not Kodi’s biologi-
cal father.
    On February 21, 2013, the juvenile court held a hearing on
the motion to exclude. At this hearing, Michael was present
and was acknowledged as “[t]he juvenile’s father.”
    In support of the motion to exclude, the guardian ad
litem presented testimony from Kari Kraenow, the Department
of Health and Human Services caseworker assigned to the
case. Following Kodi’s removal from the home, Kraenow
had talked with Shawntel and Michael about Kodi’s pater-
nity. Both Shawntel and Michael told Kraenow that Shawntel
was already pregnant when they met, but that Shawntel did
not want the biological father to be involved. Shawntel and
Michael told Kraenow that Michael signed the acknowl-
edgment of paternity because they both wanted him to be
Kodi’s father. According to Kraenow, Shawntel recognized
that “Jack D.” was Kodi’s biological father, but she identified
Michael as the “legal father.” Kraenow also testified that both
Shawntel and Michael admitted to knowing Michael was not
Kodi’s biological father when they signed the acknowledg-
ment of paternity.
    On cross-examination, Michael told a similar story regarding
why he signed the acknowledgment of paternity. He admitted
that he and Shawntel knew when they signed the acknowledg-
ment that he was not Kodi’s biological father. They signed it
because they wanted Michael “to be the father.” According to
Michael, he and Shawntel “didn’t want [the biological father]
to being [sic] any part of . . . Kodi’s life. And so [Michael]
stepped up as a man to be the father of that child.” Despite
testifying that he did not read the acknowledgment before
signing it, Michael stated that he knew the acknowledgment
was “to clarify who the parents were.” He would not admit
that he knew the acknowledgment was false when he signed
it, but seemed to believe that the biological father did not need
   Nebraska Advance Sheets
38	287 NEBRASKA REPORTS



to be involved or did not have the right to be involved because
the pregnancy was the result of an alleged rape. (Shawntel had
never filed a complaint about the alleged rape or reported it to
the authorities.)
   Evidence was adduced that Michael was facing charges and
possible incarceration for 13 felony counts. The guardian ad
litem also offered into evidence a “DNA Test Report” showing
that there was a 0-percent probability that Michael was Kodi’s
biological father.
   At the conclusion of the hearing, the juvenile court found
that the guardian ad litem had met its burden under § 43-1409
to rebut the presumption of paternity arising from the nota-
rized acknowledgment of paternity. The court found that the
acknowledgment was fraudulent because “both Shawntel . . .
and Michael . . . admitted that at the time they signed said
document they both knew that Michael . . . was not the bio-
logical father of Kodi.” Because the presumption was rebutted,
the court ruled that the acknowledgment was “of no force and
effect at this point in time.” Based on the DNA test results, the
court found that “there is a zero percent chance that [Michael]
is the biological father of Kodi.” Therefore, it concluded that
“there is nothing in the Juvenile Petition filed herein that
applies to Michael . . . as he is not the biological father of
Kodi . . . nor is he the step-parent to Kodi.” Accordingly,
the court granted the guardian ad litem’s motion to exclude
Michael and dismissed him from the proceedings.
   Michael timely appeals. Pursuant to our statutory authority
to regulate the dockets of the appellate courts of this state, we
moved the case to our docket. See Neb. Rev. Stat. § 24-1106(3)
(Reissue 2008).
                 ASSIGNMENT OF ERROR
  Michael assigns that the juvenile court erred in excluding
him as a party to the proceedings.
                         ANALYSIS
   [2,3] The juvenile court excluded Michael because it found
that the presumption of paternity arising from the notarized
acknowledgment of paternity had been successfully rebutted.
                   Nebraska Advance Sheets
	                   IN RE INTEREST OF KODI L.	39
	                        Cite as 287 Neb. 35

Our case law provides that “the proper legal effect of a signed,
unchallenged acknowledgment of paternity is a finding that the
individual who signed as the father is in fact the legal father.”
Cesar C. v. Alicia L., 281 Neb. 979, 985, 800 N.W.2d 249,
254 (2011). However, an acknowledgment of paternity can be
challenged “on the basis of fraud, duress, or material mistake
of fact.” § 43-1409. In the instant case, the juvenile court deter-
mined that the acknowledgment was fraudulent and, accord-
ingly, set it aside as having no legal effect.
   [4,5] Michael does not argue that it was error to set aside
the acknowledgment as fraudulent. In order to be considered
by an appellate court, an alleged error must be both specifi-
cally assigned and specifically argued in the brief of the party
asserting the error. J.P. v. Millard Public Schools, 285 Neb.
890, 830 N.W.2d 453 (2013). Errors assigned but not argued
will not be addressed on appeal. Peterson v. Ohio Casualty
Group, 272 Neb. 700, 724 N.W.2d 765 (2006). Therefore,
because Michael does not argue that it was error to set aside
the acknowledgment, we do not review the juvenile court’s
decision to set it aside.
   [6] Michael argues that the juvenile court erred in excluding
him from the proceedings because he “was an active physical
custodian and caregiver of [Kodi].” Brief for appellant at 6.
But he did not make that argument before the juvenile court.
When announcing its ruling, the juvenile court emphasized
multiple times that Michael was excluded only to the extent
that he was not Kodi’s legal father, as had been alleged in
the amended petition. Michael then asked whether he might
be allowed to participate on other grounds, and the juve-
nile court left open the possibility that he could participate
based on “another legal theory” besides paternity. Despite that
opportunity, the record does not reflect that Michael has made
any motions in the juvenile court to intervene or be named
as a party in Kodi’s juvenile proceedings on the basis of any
relationship besides paternity. “[A]n issue not presented to or
passed on by the trial court is not appropriate for consideration
on appeal.” Sherman T. v. Karyn N., 286 Neb. 468, 475, 837
N.W.2d 746, 753 (2013). Michael did not argue before the
   Nebraska Advance Sheets
40	287 NEBRASKA REPORTS



juvenile court that he was Kodi’s custodian. Therefore, we do
not consider that argument on appeal.
   In summary, Michael argues that he should be included as
a party on grounds not presented to the juvenile court. Yet,
he fails to challenge the juvenile court’s key decision leading
to his exclusion—the setting aside of the acknowledgment of
paternity as fraudulent. As such, the only question properly
before this court is whether the juvenile court erred in dismiss-
ing Michael from the proceedings after it had set aside the
acknowledgment of paternity.
   We find no error in this regard. Once the acknowledg-
ment was set aside, Michael could no longer claim that he
was Kodi’s legal father. And the evidence before the juvenile
court conclusively established that Michael was not Kodi’s
biological father. The acknowledgment was Michael’s sole
basis for claiming that he was Kodi’s father. Therefore, once
the acknowledgment was set aside, he had no interest in the
juvenile proceedings as a father. The juvenile court did not err
in excluding Michael, because he was neither the legal nor the
biological father.
                        CONCLUSION
   For the aforementioned reasons, we affirm the juve-
nile court’s order dismissing Michael from the juvenile
proceedings.
                                             Affirmed.
   Heavican, C.J., not participating.


                    State of Nebraska, appellee, v.
                    Gregory D. Fester II, appellant.
                                  ___ N.W.2d ___

                     Filed December 13, 2013.     No. S-13-401.

 1.	 Effectiveness of Counsel: Appeal and Error. A claim that defense counsel
     provided ineffective assistance presents a mixed question of law and fact.
     An appellate court reviews the district court’s factual findings for clear error.
     Whether defense counsel’s performance was deficient and whether the defendant
     was prejudiced by that performance are questions of law that the appellate court
     reviews independently of the district court’s decision.
