(1) At the trial of a person charged with incest, it is sufficient to prove that the female or male in respect of whom the offence is alleged to have been committed is reputed to be the lineal ascendant, descendant, or sister or brother of the other party to the incest, and it is not necessary to prove that any such person was born in lawful wedlock, or was of the whole blood.
(2) The accused person, until the contrary is proved, is presumed to have had knowledge at the time of the alleged offence of the relationship existing between him or her and the other party to the incest.