It is not abnormal to see different punishment for people under the age of 18. Good education about sex and what sexual assault does with their victims (same with guns, drugs including alcohol etc).
You can still course correct the behaviour of a 13 year old. There is also a difference between generating the porn and abusing it by sharing it etc.
The girls should be helped and the boys should be punished, but mainly their behaviour needs to be correcte
You can use the Oral B with some electric brushes to see where you have brushed and where you haven't to help you with not missing anything.