Is it reasonable to believe Mary & Joseph had other children besides Jesus?

In nearly every discussion about the Perpetual Virginity of Mary that I've come across, the debate almost always comes down to whether the "brothers and sisters" mentioned a few times in the Gospels were biological children or if this was just an ancient way of referring to cousins (which I hold to). But what if it was neither? The past few days, I got the inspiration to realize that there is indeed another possibility that Protestants don't consider: adoption! Why not? Remember that the underlying actual goal of the Protestant side is to attack Catholicism by attacking Mary, so if the "brothers and sisters" aren't biological children then their anti-Catholic mission has failed. The adoption possibility doesn't seem to be an explanation that I've ever come across, which is strange because it easily counters the Protestant when they reject the standard Catholic cousin explanation. It was actually very common in ancient times for parents to die of diseases and such, since there wasn't modern medicine or sanitation. So it was not uncommon for children of the same region, neighborhood, relatives, tribe, etc, to adopt those orphaned children. Could this be why James, the "brother" of Jesus, speaks so highly of taking care of orphans? (James 1:27) The genealogy lists that Matthew and Luke give list different forefathers at some points, but this is easily explained by the reality that some of those sons/fathers were adopted, and thus lineages crossed, but since it was all within the same Tribe of Judah, it was ultimately the same lineage. What is a Protestant really going to do if you respond by saying "yes, but these were adopted children"? The Protestant will realize that they cannot simply presume, and thus their argument is instantly deflated. Plus, we are all truly the brothers of Jesus by adoption in the spiritual sense, and would even extend that into being adopted by Mary (and Joseph), which is how many Catholic spiritual writers have understood the "rest of her children" in reference to Mary in Revelation 12:17.

"They were not yet born, nor done anything good nor bad" - a fresh look at Romans 9:10-13

I wanted to share some further insights I've had on Romans 9, stemming from an earlier series (here). This time we will focus on the famous passage in Romans 9:10-13, which says:

10 And not only so, but also when Rebekah had conceived children by one man, our forefather Isaac, 11 though they were not yet born and had done nothing either good or bad - in order that God's purpose of election might continue, not because of works but because of him who calls - 12 she was told, “The older will serve the younger.” 13 As it is written, “Jacob I loved, but Esau I hated.”

This passage has been the subject of considerable debate for centuries. One camp has tended to read the text as a cold, hard assertion of God's Sovereignty, where God elects us to salvation or damnation before we existed, apart from any consideration of our good/bad behavior. At first glance, it does seem to read that way. But I think this is a serious distortion of the text as well as the other themes of Scripture. Consider the following points.

First, Paul introduces this section by calling upon "our forefather Isaac" (9:10), which not only continues the same lesson of Abraham in the prior verses (9:7-9), but has the same phraseology as the "our forefather Abraham" in Romans 4:1. Recall that in Romans 4 the issue was also "not of works," as it is here in Romans 9:11. I believe I have convincingly shown in my Revisiting Abraham's reckoned as righteousness series, particularly part 2 (here), that Paul's real focus in Romans 4 was about how Abraham tried to bring about the promised heir of Genesis 15 by sleeping with Hagar in Genesis 16, thus producing the illegitimate heir Ishmael, who was technically Abraham's biological son. In the lesson of Abraham, Paul is saying mere biological descent isn't sufficient to determine who make up God's Chosen Children. Paul uses the language of "flesh" and "works" as closely related, with works meant to show the Israelite superior biological lineage over that of the inferior Gentiles (here). What this means is that when Paul shifts to "also our father Isaac," the same theme continues: now differentiating between Isaac's biological children, Jacob and Esau. So the lesson thus far is not about unconditionally sending people to heaven or hell apart from their deeds, but rather a more practical yet mysterious looking back at a biological/ancestry issue.

Second, we now turn to the most controversial point "though they were not yet born," which most people mistakenly interpret to mean "before they even existed". The reality is, when this situation took place, both Jacob and Esau fully existed, as babies within Rebekah's womb:

Genesis 25: 21 And Isaac prayed to the Lord for his wife, because she was barren, and Rebekah conceived. 22 The children struggled together within her, and she said, “Why is this happening to me?” 23 And the Lord said to her, “Two nations are in your womb, and two peoples from within you shall be divided; the one shall be stronger than the other, the older shall serve the younger.”

Once you admit the fact that God said this while the children were alive and active within Rebekah's womb, the "before the even existed" reading is instantly discredited. What of the "before they had done anything good or bad"? They were alive and active, yet it wasn't until later in life when they did in fact do good/bad actions. So God was simply making a prophecy during Rebekah's pregnancy of how things would turn out. The "struggling within her" certainly means Jacob and Esau were in some manner fighting each other to be firstborn, with the stronger man winning the birth war, thus Esau being born first. This biological superiority plays out with their "works" showing their dominant physical features. This again ties to the firstborn-yet-not-heir theme as Abraham with Ishmael, and God prophetically saying the older Ishmael will serve the younger Isaac.