V. T., a 14-year-old juvenile, was adjudged a delinquent after the juvenile court found that he had committed acts constituting the offense of statutory rape of a two-year-old infant. The evidence disclosed V. T. went to a friend’s house late in the morning of the alleged rape. Shortly thereafter, the friend left to walk an aunt’s dog, leaving V. T. alone with the friend’s two-year-old sister. Prior to leaving to walk the dog, the friend had changed the baby’s diaper several times and noted nothing unusual. When the friend returned about 15 minutes later, the baby was crying and there was blood on the diaper.
Physical evidence of the tear, bruising and swelling in the vaginal area of the two-year-old infant was sufficient to cause an examining physician to conclude that the infant’s injuries were most probably caused by a male sex organ rather than some other object. Upon interrogation, V. T. admitted that he had sexually penetrated the child while his friend had gone to walk the dog. At trial, V. T. disputed the admissibility of the confession and the sufficiency of the evidence to support the juvenile court’s findings in view of the evidence of an alibi and the lack of direct evidence that the child had been sexually penetrated and if so, by him. Held:
1. In the enumeration of error relating to the sufficiency of the circumstantial evidence to support the finding of delinquency, we disagree with the theories advanced by V. T. Whether in a given case *473circumstances are sufficient to exclude every reasonable hypothesis except the guilt of the accused is ordinarily a question to be resolved by the trier of fact. An appellate court has no yardstick by which to determine what in a given case is a reasonable hypothesis except to rely on the informed and weighed conclusions of a trier of fact. In the case sub judice, the trier of fact (the juvenile court judge) observed and heard the witnesses, and certainly is best qualified to judge the reasonableness of an hypothesis raised by evidence or its lack than by this court which is restricted to issues of law. Estep v. State, 154 Ga. App. 1 (267 SE2d 314). Where the trier of fact was authorized to find that the evidence, though circumstantial, was sufficient to exclude every reasonable hypothesis save that of guilt, as an appellate court we will not disturb that finding unless the verdict of guilty is unsupportable as a matter of law. Staymate v. State, 237 Ga. 661 (1) (229 SE2d 421); Bowen v. State, 139 Ga. App. 190, 192 (228 SE2d 187). We find the evidence in this case to be sufficient to convince any rational trier of fact beyond a reasonable doubt that V. T. committed the acts by reason of which he was alleged to be delinquent. Brown v. State, 250 Ga. 66, 67 (1) (295 SE2d 727); Mulkey v. State, 250 Ga. 444, 447 (5) (298 SE2d 487). This enumeration is without merit.
2. With reference to the admissibility of V. T.’s confession (or admission against interest), the state first offered evidence that same was made freely and voluntarily after the juvenile had been advised of his Miranda rights and same was made not under any threats or any hope of reward with his mother present, although she was not in the same room at the same time he admitted the statements to the investigator. The officer testified that V. T.’s mother did not raise any objection to the statement and was shown the statement after it was typed, read it, agreed to it and signed it first. Whereupon, he was requested to read the statement into evidence. Counsel for V. T. then objected to the admission of the statement being read into evidence contending “the subject matter of the statement was taken and extracted from [V. T.] when his mother was not present.” The following colloquy then occurred. “Court: In other words, you are questioning the validity of the statement? [Counsel]: Absolutely. Court: Okay, at that point in time, gentlemen, it’s up to him to prove that it was not freely and voluntarily taken ... it’s up to [defendant] now to prove that it was not freely and voluntarily taken as I understand the rules.”
The defense proceeded to call witnesses to show the lack of voluntariness which was followed by rebuttal by the state. Whereupon, the court ruled on the admissibility of the statement as follows: “I’m going to let it in. Your objections are noted for the record.”
*474First of all, it is not necessary that a parent of a child be present during the interrogation of the child, as long as protection is taken to protect the child’s constitutional rights. See Marshall v. State, 248 Ga. 227, 228 (2) (282 SE2d 301). Here, however, the mother was present and made no objection to the taking of the statement which was reduced to writing and signed by her prior to her son signing it, although she thereafter contended it was under duress. The standard for determining whether or not a confession (or admission) was voluntary is the preponderance of the evidence standard. See Brooks v. State, 244 Ga. 574, 581 (2) (261 SE2d 379). Here the juvenile court judge, as the trier of fact, must use the preponderance of evidence standard and be satisfied that the confession was voluntary. See High v. State, 233 Ga. 153, 154 (210 SE2d 673). The decision of the trial court on this point will not be disturbed on appeal unless there is obvious error. See Ingram v. State, 137 Ga. App. 412, 413 (1) (224 SE2d 527); Johnson v. State, 233 Ga. 58 (209 SE2d 629).
Here, however, it is contended that the court shifted the burden of proof to the juvenile (defendant). We disagree.
“ ‘The term “burden of proof’ has a dual meaning: (a) Generally, the burden of proof rests where the pleadings place it; this is recognized as the burden of pleadings, and remains thus placed throughout the trial, (b) The burden of testimony or evidence is shifting, and, during the progress of a trial may alternately shift on facts or issues from one party to the other. As to the burden of pleadings, the trial court has no discretion; it is a matter of law. As to the burden of testimony or evidence, he has a discretion to determine whether or not the evidence produced, together with attending rules of presumption and procedure, under the particular case, has shifted it.’ ” Central of Ga. R. Co. v. Hester, 94 Ga. App. 226, 237-238 (94 SE2d 124); Dept. of Revenue v. Stewart, 67 Ga. App. 281 (4) (20 SE2d 40). See also Hawkins v. Davie, 136 Ga. 550, 552 (71 SE 873). Here, the state’s witness (an investigator) testified that V. T. was advised of his Miranda rights and that the statement, marked state’s Exhibit Number 9 was made voluntarily by V. T. The witness stated that V. T. was not threatened in any way and was not offered any inducement or reward. He further stated that V. T.’s mother read the typed statement and without raising any objection, signed it. Thereafter, the juvenile court judge stated: “[I]t’s up to [V. T.’s attorney] now to prove it [V.T.’s statement] was not freely and voluntarily taken ...”
Therefore, it was in the juvenile court judge’s sound discretion to determine that the burden of introducing testimony, or the burden of evidence (not the ultimate burden of proof) moved to V. T. Accordingly, no shifting of the ultimate burden of proof took place in this case, and there is no merit in this enumeration of error.
*475Decided September 27, 1983 Rehearing denied October 18, 1983 Walter W. Kelley, for appellant. Robert E. Baynard, for appellee.Judgment affirmed.
Shulman, C. J., Deen, P. J., Quillian, P. J., Banke, Carley, Sognier and Pope, JJ., concur. Birdsong, J., dissents.