Parents of new alleged victims recently came forward after St-Jacques was arrested and charged in December, bringing the total number of alleged victims to 15.
St-Jacques, 22, allegedly told parents of autistic children that he too was autistic and needed help understanding how to clean himself.
It's alleged he asked the parents to show him by demonstrating on their children, during which he then allegedly took photos and videos without the parents' knowledge.
Crown Prosecutor Roxane Laporte said St-Jacques contacted parents through Facebook or Twitter.
He was already facing 17 charges — 14 counts of child pornography and three counts of sexual touching.
St-Jacques, who has been in custody for the last three months, will appear in court on Friday to seek bail.