None of this matters. the Bible says nothing about Mary’s perpetual virginity ... period.
The other side points out scripture where it names the brothers of Jesus, but do not provide any scripture to prove Mary had other children, neither side proves anything.
While technically true, the Protestant position has the convenience of leaning upon the norm - IOW, without some special circumstance being otherwise mentioned in the Scriptures, one can readily assume the Hebrew conventions of normalcy apply. Since no exception is mentioned (like with the 12 sons of Abraham from two different mothers, as specified), the normal condition seems to apply.
The Roman church must fall back to unattributed, spurious works to grasp for a condition wherein Mary can remain ever virgin - Something not required in the Scriptures, and having no value whatsoever in the Gospel message... Ergo the rather strained outcome with many unnecessary convolutions. But they *need* it to be true, lest the entire ecosystem of mariology should crumble into nothing, and they can't have that.
Essays for Lent: Mary Ever-Virgin
Why is the perpetual virginity of Mary so important to Catholics? [Ecumenical Vanity]
Is the Perpetual Virginity of Mary a Biblical View?
Aeiparthenos (An Anglo-Catholic Priest on Mary's Perpetual Virginity)
The Heõs Hou polemic is over: Radio Debate Matatics VS White & Svendsen on Perpetual Virginity Mary
The Early Church Fathers on Mary’s Perpetual Virginity - Catholic/Orthodox Caucus
The Heõs Hou polemic is over: Radio Debate Matatics VS White & Svendsen on Perpetual Virginity Mary
Luther, Calvin, and Other Early Protestants on the Perpetual Virginity of Mary
Luther, Calvin, and Other Early Protestants on the Perpetual Virginity of Mary