1. A person eighteen years of age or older commits continuous sexual abuse of a child when the person engages in any combination of three or more acts of sexual abuse in violation of section 709.3 or 709.4, with the same child, and at least thirty days have elapsed between the first and last acts of sexual abuse.
 2. A person who commits continuous sexual abuse of a child is, upon conviction, guilty of a class “B” felony. Notwithstanding section 902.9, subsection 1, paragraph “b”, a person convicted of a violation of this section involving any combination of three or more acts of sexual abuse that includes a violation of section 709.3 or 709.4 shall be confined for no more than fifty years.
 3. If a jury is the trier of fact, members of the jury must unanimously agree that three or more acts of sexual abuse in violation of section 709.3 or 709.4 were committed with the same child and at least thirty days have elapsed between the first and last acts of sexual abuse. The jury does not need to unanimously agree which specific acts were committed or the exact date when those acts were committed.
 4. Any other sexual abuse offense involving the same child shall not be charged in the same proceeding as a charge under this section unless the other sexual abuse offense occurred outside of the time period charged under this section or the other sexual abuse offense is charged in the alternative.
 5. A person shall be charged with only one count under this section unless more than one child is involved in the offense. If more than one child is involved, a separate count may be charged for each child.
 6. Each act of sexual abuse committed under section 709.3 or 709.4 shall be considered a lesser included offense to the crime of continuous sexual abuse of a child under this section.