Regarding the findings of Dra. Valdez that her physical examination on the victims shows no evident injury, this Court had already ruled that "a medical examination of the victim is not indispensable in a prosecution for rape inasmuch as the victim's testimony alone, if credible, is sufficient to convict the [accused] of the crime."[20] Appellant denies being at the house of "CCC" during the incidents. However, he failed to provide an account of his whereabouts such that it was physically impossible for him to have committed the crimes. Appellant's unsubstantiated denial must fail in light of the categorical testimonies of the victims that it was he who molested them. Notably, appellant's belabored attempt to reverse his conviction is essentially anchored on credibility. The general rule is that "this Court will not disturb the findings of the trial court as to the credibility of witnesses, considering that it is in a better position to observe their candor and behavior on the witness stand."[21] However, this principle does not preclude a reevaluation of the evidence to determine whether material facts or circumstances have been overlooked or misinterpreted by the trial court.[22] Consistent with the principle that an appeal in a criminal action opens the whole case for review, we shall now determine whether the evidence of the prosecution is sufficient to sustain the conviction of the appellant for qualified rape and statutory rape. Rape is committed by having carnal knowledge of a woman with the use of force, threat or intimidation or when she is under 12 years of age or is demented. Where the victim is below 12 years old, the only subject of inquiry is whether "carnal knowledge" took place. Carnal knowledge is "the act of a man having sexual intercourse or sexual bodily connections with a woman".[23] There must be proof that his penis touched the labias of the victims or slid into their female organs and not merely stroked the external surface thereof, to produce a conviction of rape by sexual intercourse.[24] ''AAA" recounted the details on how the alleged rape was committed as follows: The alleged rape committed on the first week of October 2001 (Criminal Case No. 07-CR-6765) xxxx Q: And what did he do after he made you lie down on the sofa? A: He went to get cooking oil and poured it on his penis and he undressed me and he also poured cooking oil on my vagina.