No doubt it may be interesting to investigate, but other posters are correct in saying it doesn’t have any real theological significance. Any brothers and sisters would have been HALF brothers because they were fathered by Joseph.
If you want to see the living brothers and sisters of Christ, look at the places his followers gather. There will be many there and you can actually talk to them...
You're getting into some pretty deep philosophical territory there. When you say Jesus was the son of God, does that mean that he had 23 of God's chromosomes? Does God have 23 human chromosome pairs? If not, and if He chose which genes to give to Mary's baby, who says He didn't choose Joseph's?
Under Jewish law at the time -- and for that matter, under common law up to today -- a child born within a marriage is presumed to be the child of both spouses, absent proof to the contrary. So legally, Jesus was the son of Joseph. Ethically and emotionally, Joseph loved and raised Jesus as his own. What I'm suggesting is that this might also have been true biologically.