The husband of the mother of a child is presumed to be that child's parent until that presumption is disestablished. In New York State, when a child is born to a married mother, a court may decline to consider DNA evidence when it is not in the best interests of the child to do so. In substance (although not exactly from a legal perspective), a failure to promptly contest the paternity of a child of a married mother gives rise to a de facto adoption.
Article 5 of the New York Family Court Act in its definitions section, § 512, makes clear that it applies only to children born out of wedlock (and it too has an equitable paternity term at § 532). So, the statutory deadline in Article 5 allowing a child with no legally determined father to have a determination made at any time before the child turns age twenty-one does not apply to this case.
Instead, this case is governed by New York Family Court Act, Article 4. New York Family Court Act § 418(a), which governs paternity cases where a child is born during a marriage provides that:
(a) The court, on its own motion or motion of any party, when
paternity is contested, shall order the mother, the child and the
alleged father to submit to one or more genetic marker or DNA marker
tests of a type generally acknowledged as reliable by an accreditation
body designated by the secretary of the federal department of health
and human services and performed by a laboratory approved by such an
accreditation body and by the commissioner of health or by a duly
qualified physician to aid in the determination of whether the alleged
father is or is not the father of the child. No such test shall be
ordered, however, upon a written finding by the court that it is not
in the best interests of the child on the basis of res judicata,
equitable estoppel or the presumption of legitimacy of a child born to
a married woman. The record or report of the results of any such
genetic marker or DNA test shall be received in evidence, pursuant to
subdivision (e) of rule forty-five hundred eighteen of the civil
practice law and rules where no timely objection in writing has been
made thereto. Any order pursuant to this section shall state in plain
language that the results of such test shall be admitted into
evidence, pursuant to rule forty-five hundred eighteen of the civil
practice law and rules absent timely objections thereto and that if
such timely objections are not made, they shall be deemed waived and
shall not be heard by the court. If the record or report of results
of any such genetic marker or DNA test or tests indicate at least a
ninety-five percent probability of paternity, the admission of such
record or report shall create a rebuttable presumption of paternity,
and, if unrebutted, shall establish the paternity of and liability for
the support of a child pursuant to this article and article five of
this act.
If DNA evidence is considered, the biological father will be determined to be the father, but if it is not considered, the husband will continue to be the legal father.
A leading case exploring when the best interests of the child test prevails over DNA evidence from New York is In the Matter of Shondel J., v. Mark D., 853 N.E.2d 610 (N.Y. July 6, 2006). In a key passage, it states:
Equitable estoppel is gender neutral. In Matter of Sharon GG. v Duane
HH. (63 2 859 [1984], affg 95 AD2d 466 [3d Dept 1983]), we affirmed an
order of the Appellate Division dismissing a paternity petition in
which a mother sought to compel her husband to submit to a blood test
as a means of challenging his paternity. We agreed with the Appellate
Division that the mother should be estopped. As that court pointed
out, the mother expressed no question about her child's paternity
until some two and a half years after the child's birth. She had held
the child out as her husband's, accepted his support for the child
while she and her husband lived together and after they separated, and
permitted her husband and child to form strong ties together.
Estoppel may also preclude a man who claims to be a child's biological
father from asserting his paternity when he acquiesced in the
establishment of a strong parent-child bond between the child and
another man. The rationale is that the child would be harmed by a
determination that someone else is the biological father. For example,
in Purificati v Paricos (154 AD2d 360 [2d Dept 1989]), a boy's
biological father who did not seek to establish his paternity until
more than three years after the child's birth, and who acquiesced as a
relationship flourished between the boy and his mother's former
husband, was estopped from claiming paternity. The courts "impose
equitable estoppel to protect the status interests of a child in an
already recognized and operative parent-child relationship" ( In re
Baby Boy C., , 84 NY2d 91, 102 n [1994]).
Finally, the Appellate Division has repeatedly concluded that a man
who has held himself out to be the father of a child, so that a
parent-child relationship developed between the two, may be estopped
from denying paternity.2 Where a child justifiably relies on the
representations of a man that he is her father with the result that
she will be harmed by the man's denial of paternity, the man may be
estopped from asserting that denial.3 . . .
Given the statute recognizing paternity by estoppel, a man who harbors
doubts about his biological paternity of a child has a choice to make.
He may either put the doubts aside and initiate a parental
relationship with the child, or insist on a scientific test of
paternity before initiating a parental relationship. A possible result
of the first option is paternity by estoppel; the other course creates
the risk of damage to the relationship with the woman. It is not an
easy choice, but at times, the law intersects with the province of
personal relationships and some strain is inevitable. This should not
be allowed to distract the Family Court from its principal purpose in
paternity and support proceedings -- to serve the best interests of
the child.
This continues to be good law. See, e.g. In the Matter of Thomas T. v. Luba R., 148 A.D.3d 912 (March 15, 2017) (paternity by estoppel established when child at age four did not know biological father's name and had established a strong father-child-like bond with mother's currently partner citing Shondel).
Under the circumstances, if any of the three parties: the mother, the husband, or the biological father, sought to prevent consideration of DNA evidence after ten to fifteen years of marriage during which paternity was not denied, it is very likely that the Court would agree and not change the legal paternity of the child.
In this case, the biological father would not gain legal visitation rights and would not owe child support, and neither the husband nor the mother would lose their presumed parent status, nor would they be entitled to child support.
If the husband, mother and biological father mutually agreed otherwise, the paternity by estoppel argument might be overcome and any issue of support would be governed by the mutual agreement (although a guardian ad litem for the child might be appointed sua sponte by the Court and have standing to object to the agreement on behalf of the child notwithstanding the mutual agreement of the other three parties). This would terminate husband's status as a parent and entitle biological father to visitation. But, otherwise paternity by estoppel would prevail.
Incidentally, this statute and case law position is constitutional. The U.S. Supreme Court has held that a man who conceives a child with a married woman does not have a due process right in establishing his paternity of the child, so any right that the biological father may have arises from statute and the common law, rather than from the U.S. Constitution. Michael H. v. Gerald D. (U.S. 1989).