I am not wrong. Look up the Greek. I did. Adopted brothers and sisters. Hmmmmm. Interesting possibility. Wasn't aware Mary and Joseph ran an orphanage. Maybe they were baby brokers.
And as far as being a son or daughter of Mary or Joseph, no I can't find that phrase. So I guess that means that they were neither and were part of Francis Crick's Panspermia theory. They were seeded here by Space Aliens.
You really are impossible!
So, your contention is that it would be totally impossible that the Holy Family might have taken in relatives' children who were orphaned? And I am not saying that this is the case, it is more likely that they were cousins who grew up with Jesus. The point is the notion that the Virgin Mary had other children was NEVER mentioned prior to a few hundred years ago.
As an aside, one problem that will always exist with the Gospels is the fact that although they were written in Greek, the words our Lord spoke were in Aramaic. And Aramaic DOESN'T HAVE A WORD FOR COUSIN.