“‘ELIMINATE THE PHRASE “CARNAL KNOWLEDGE OF ANY FEMALE, NOT HIS WIFE, WHO HAS NOT ATTAINED THE AGE OF 16 YEARS” AND SUBSTITUTE A FEDERAL, SEX-NEUTRAL DEFINITION OF THE OFFENSE. … A PERSON IS GUILTY OF AN OFFENSE IF HE ENGAGES IN A SEXUAL ACT WITH ANOTHER PERSON. … [AND] THE OTHER PERSON IS, IN FACT, LESS THAN 12 YEARS OLD.'”