(a) In indictments for sex offense it is not necessary to allege every matter required to be proved on the trial; but in the body of the indictment, after naming the person accused, the date of the offense, the county in which the sex offense was allegedly committed, and the averment "with force and arms," it is sufficient in describing a sex offense to allege that the accused person unlawfully, willfully, and feloniously did engage in a sex offense with the victim, naming the victim, by force and against the will of the victim and concluding as required by law. Any bill of indictment containing the averments and allegations named in this section is good and sufficient in law as an indictment for a first degree sex offense and will support a verdict of guilty of a sex offense in the first degree, a sex offense in the second degree, an attempt to commit a sex offense, or an assault.
(b) If the victim is a person under the age of 13 years, it is sufficient to allege that the defendant unlawfully, willfully, and feloniously did engage in a sex offense with a child under the age of 13 years, naming the child, and concluding as required by law. Any bill of indictment containing the averments and allegations named in this section is good and sufficient in law as an indictment for a sex offense against a child under the age of 13 years and all lesser included offenses.
(c) If the victim is a person who has a mental disability or who is mentally incapacitated or physically helpless, it is sufficient to allege that the defendant unlawfully, willfully, and feloniously did engage in a sex offense with a person who had a mental disability or who was mentally incapacitated or physically helpless, naming the victim, and concluding as required by law. Any bill of indictment containing the averments and allegations named in this section is good and sufficient in law for a sex offense against a person who has a mental disability or who is mentally incapacitated or physically helpless and all lesser included offenses.