When ds was 14 a female classmate sent him (unsolicited) a picture of her naked from the waist up - she sent it to half a dozen boys.
Despite the fact that he immediately deleted the photograph and blocked her, he was called in by the school and threatened with suspension and police action - the reason given was that he should have reported it to someone confused. It turned out that one of the boys had forwarded the photograph to others, and another had sent back a picture of himself naked. The resulting hoo-ha involved parents and police (understandably).
In the end, ds was let off with a warning; the boy who forwarded the picture was suspended and the other boy excluded from school. Fair enough, one might say, but there was no punishment for the girl at all. She was classed as "vulnerable" and given counselling and extra support.
While I get she probably needed it, it seems to me that since all the kids were the same age, the whole thing was started by the girl, the boys didn't do anything that she didn't do (send "child porn" over their phones), their treatment by the school was very different based on their sex.
So the girl sent a naked photo of herself to her "boyfriend", who then forwarded it to all of his friends, including your son. And you think this was fine because she "started" it?
How disgusting.
You get that many girls can be pressured into sending naked pictures. Most of the sexts are of girls bodies, not male bodies. The same boys who ask for pictures then slut shame and bully girls over sending them. Teenage girls have killed themselves and had to leave school over sending sexts to their boyfriends".
When boys are slut shamed for having sex, it'll be the same. If my son hung around with a group of boys and engaged in this behavior, I'd be ashamed. Horrific.