Aggression towoards my daughters friends

I have a 2 year old male apbt who is as friendly as can be to adults but recently has become agressive with children.
My daughters two friends in particular he seems to hate and if he even see's them he growls and will even lunge at the window with obvious dislike.

I don't know what prompted this as he has been fine with kids and has never been tormented or teased or anything remotely like that.
I am at my wits end and am really thinking I may have to get rid of him because of this.
If anyone can give me any solution or cureI would appreciate it. It is not socialization as he has been around both adults and children his whole life with no problems until recently.

Thanks

Is it towards ALL your daughter's friends? Or just the two? If it's just the two, then I would lean towards them teasing. You can't possibly watch the dog all the time the friends are over...can you? Dogs can't tell you who they like and don't like, aside from growling. Since it's restricted to certain people, it's for a reason.

If it's everyone...is this animal fixed? It may be hormones.

I agree if it is only the 2 then there is some form of teasing or torment. Dogs do not decide after a long period of time to become aggressive with someone they have known a long time for no apparent reason.

He does this ONLY with these two children?

Any sudden change in behavior - sudden onset of aggression - should be checked out by the vet. Thyroid problems can cause aggression, or there may be something else going on.

Are You Sure They Didnt Do Something To The Dog To Piss Him Off???