DECISION ORDER
ORDERED that the order is affirmed insofar as appealed from, with costs.
It is well settled that, as between a parent and a nonparent, the parent has the superior right to custody that cannot be denied unless the nonparent establishes that the parent has relinquished that right due to surrender, abandonment, persistent neglect, unfitness, or other extraordinary circumstances ( see Matter of Bennett v. Jeffreys, 40 N.Y.2d 543, 546; Matter of Dungee v. Simmons, 307 A.D.2d 312). The burden of proof is on the nonparent to prove such extraordinary circumstances ( see Matter of Darlene T., 28 N.Y.2d 391, 394). Once there is a finding of extraordinary circumstances, a best interests determination is triggered ( see Matter of Williams v. Dunston, 202 A.D.2d 681,682; Matter of Nadia Kay R., 125 A.D.2d 674, 678).
Here, the Family Court determined that the grandparents failed to make a threshold showing of the existence of extraordinary circumstances. Such factual findings, which are predicated on the Family Court's evaluation of the testimony, character, temperament, and sincerity of the parties, are entitled to great deference and may not be set aside where, as here, they have a sound and substantial basis in the record ( see Matter of Scala v. Parker, 304 A.D.2d 858, 859; Matter of Cole v. Goodrich, 272 A.D.2d 792, 793-794; Matter of Tompkins v. Sterling, 267 A.D.2d 315, 316).
The petitioners' further contention that the Family Court erred in failing to, sua sponte, conduct an in camera interview of the children (who were, respectively, seven and four years old at the time) has not been preserved for appellate review ( see Matter of Nielsen v. Nielsen, 225 A.D.2d 1050; Matter of Newton v. Newton, 210 A.D.2d 337). In any event, this contention is without merit. The decision to conduct an in camera interview of children involved in custody proceedings is a matter committed to the sound discretion of the Family Court ( cf. Matter of Lincoln v. Lincoln, 24 N.Y.2d 270, 273-74). Where, as here, the children are of very young age, and neither the parties nor the Law Guardian requests an in camera interview, the Family Court's failure to conduct such an interview, sua sponte, does not constitute an improvident exercise of discretion ( see Matter of Thompson v. Thompson, 267 A.D.2d 516, 519; Matter of Farnham v. Farnham, 252 A.D.2d 675, 677).
Contrary to the petitioners' contentions, the Family Court's determination not to follow the Law Guardian's recommendations was not arbitrary ( see Matter of Johnson v. Johnson, 309 A.D.2d 750, 751; Matter of Martin V. v. Karen Beth G., 305 A.D.2d 305, 306; Matter of Griffin v. Scott, 303 A.D.2d 504, 505).
The petitioners' remaining contentions are without merit.
RITTER, J.P., S. MILLER, H. MILLER and CRANE, JJ., concur.