Speaking of Saint Joseph, I'm often struck by how some folks continue to view adoptive children as, in some sense, not the "real" children of their adoptive parents. It is a strangely old-fashioned, parochial view, I think, to regard biological children as somehow more "authentic" than adoptive children. You don't run into this attitude all that often any more, but it has not disappeared by any means. When I was a kid it was endemic. You still find references to it in the popular culture--claims made by mean siblings that "You must be adopted" to siblings who aren't really adopted, or "I must be adopted" being said as a way of distancing oneself from the wacky shenanigans of the rest of the family. I suspect that these kinds of jokes are not all that funny to kids who really are adopted and who may have been struggling to come to terms with their status.
There are two manifestations of adoptive status in the Christian religion that ought to make us think twice about that sort of attitude. The first and most obvious is the relationship between Our Lord and Saint Joseph. Jesus, the Martyrology reads, "wished to be called the son of Joseph", and "He was obedient to him just as a son to his father". The second is the status of every Christian as an adoptive heir to the Kingdom of God. Through Christ, who lived as an adoptive child, God has adopted all of us as His children. That status makes us ontologically different, and the relationship that exists between us and God is no less authentic for being an adoptive relationship.
Whether thoughts along these lines will serve to comfort those who struggle with the fear that their "natural" parents somehow didn't want them or love them enough to keep them is perhaps difficult to know with any certainty. The Gospel message itself doesn't always comfort everyone, even though it should. Human nature is too weak to understand what it does not experience for itself, to paraphrase Plato.