In In re I.J. (2013) 56 Cal.4th 766, the California Supreme Court considered the question of the circumstances under which sexual abuse of a child of one gender can support a finding of substantial risk of sexual abuse of a child of the opposite gender. In considering this question, the court held that "'the broad language of subdivision (j) clearly indicates that the trial court is to consider the totality of the circumstances of the child and his or her sibling in determining whether the child is at substantial risk of harm, within the meaning of any of the subdivisions enumerated in subdivision (j).'" (I.J., supra, 56 Cal.4th at p. 774.) The court held that subdivision (j), by listing these factors, "implies that the more egregious the abuse, the more appropriate for the juvenile court to assume jurisdiction over the siblings. . 'Some risks may be substantial even if they carry a low degree of probability because the magnitude of the harm is potentially great. . . . . . . . . . Conversely, a relatively high probability that a very minor harm will occur probably does not involve a "substantial" risk. Thus, in order to determine whether a risk is substantial, the court must consider both the likelihood that harm will occur and the magnitude of potential harm . . . .' . In other words, the more severe the type of sibling abuse, the lower the required probability of the child's experiencing such abuse to conclude the child is at a substantial risk of abuse or neglect under section 300. If the sibling abuse is relatively minor, the court might reasonably find insubstantial a risk the child will be similarly abused; but as the abuse becomes more serious, it becomes more necessary to protect the child from even a relatively low probability of that abuse." (I.J., supra, 56 Cal.4th at p. 778.) The court in I.J. considered "whether a father's sexual abuse of his daughter supports a determination that his sons are juvenile court dependents when there is no evidence the father sexually abused or otherwise mistreated the boys, and they were unaware of their sister's abuse . . . ." (I.J., supra, 56 Cal.4th at p. 770.) In I.J., over the course of three years, the father repeatedly sexually abused his oldest daughter, including fondling, digital penetration of her vagina, forcible rape, and oral copulation. The father also forced his daughter to watch pornographic videos with him. (Id. at p. 771.) In concluding that the victim's sister and brothers were at substantial risk of sexual abuse, the court focused on the duration and nature of the sexual abuse inflicted on the oldest daughter by the father. The court held that "a father's prolonged and egregious sexual abuse of his own child may provide substantial evidence to support a finding that all his children are juvenile court dependents." (Id. at p. 770.) The court clarified that "in upholding the assertion of jurisdiction in this case, we are not holding that the juvenile court is compelled, as a matter of law, to assume jurisdiction over all the children whenever one child is sexually abused. We merely hold the evidence in this case supports the juvenile court's assertion of jurisdiction." (I.J., supra, 56 Cal.4th at p. 780.)