Welf. & Inst. Code, § 355.1

(a) Where the court finds, based upon competent professional evidence, that an injury, injuries, or detrimental condition sustained by a minor is of a nature as would ordinarily not be sustained except as the result of the unreasonable or neglectful acts or omissions of either parent, the guardian, or other person who has the care or custody of the minor, that finding shall be prima facie evidence that the minor is a person described by subdivision (a), (b), or (d) of Section 300.

(b) Proof that either parent, the guardian, or other person who has the care or custody of a minor who is the subject of a petition filed under Section 300 has physically abused, neglected, or cruelly treated another minor shall be admissible in evidence.

(c) The presumption created by subdivision (a) constitutes a presumption affecting the burden of producing evidence.

(d) Where the court finds that either a parent, a guardian, or any other person who resides with, or has the care or custody of, a minor who is currently the subject of the petition filed under Section 300 (1) has been previously convicted of sexual abuse as defined in Section 11165.1 of the Penal Code, (2) has been previously convicted of an act in another state that would constitute sexual abuse as defined in Section 11165.1 of the Penal Code if committed in this state, (3) has been found in a prior dependency hearing or similar proceeding in the corresponding court of another state to have committed an act of sexual abuse, or (4) is required, as the result of a felony conviction, to register as a sex offender pursuant to Section 290 of the Penal Code, that finding shall be prima facie evidence in any proceeding that the subject minor is a person described by subdivision (a), (b), (c), or (d) of Section 300 and is at substantial risk of abuse or neglect. The prima facie evidence constitutes a presumption affecting the burden of producing evidence.

(e) Where the court believes that a child has suffered criminal abuse or neglect, the court may direct a representative of the child protective agency to take action pursuant to subdivision (i) of Section 11166 of the Penal Code.

(f) Testimony by a parent, guardian, or other person who has the care or custody of the minor made the subject of a proceeding under Section 300 shall not be admissible as evidence in any other action or proceeding.