"The Bible seems to suggest"? Since when is a "seeming suggestion" in somebody's opinion authoritative for Christians?
I won't do "seeming suggestions". I'll present three facts:
A new lie about me is being circulated. I am supposed to have preached and written that Mary, the mother of God, was not a virgin either before or after the birth of Christ, but that she conceived Christ through Joseph and had more children after that. – Martin Luther, “That Jesus Christ Was Born a Jew,” in Luther’s Works, vol. 45, ed. Walther I. Brand, 1962, Muhlenberg Press, p. 199.John Calvin:
Helvidius displayed excessive ignorance in concluding that Mary must have had many sons, because Christ’s "brothers" are sometimes mentioned. (Harmony of Matthew, Mark and Luke, sec. 39 [Geneva, 1562], vol. 2 / From Calvin’s Commentaries, translated by William Pringle, Grand Rapids, Michigan: Eerdmans, 1949, p.215; on Matthew 13:55)
[On Matt 1:25:] The inference he [Helvidius] drew from it was, that Mary remained a virgin no longer than till her first birth, and that afterwards she had other children by her husband . . . No just and well-grounded inference can be drawn from these words . . . as to what took place after the birth of Christ. He is called "first-born"; but it is for the sole purpose of informing us that he was born of a virgin . . . What took place afterwards the historian does not inform us . . . No man will obstinately keep up the argument, except from an extreme fondness for disputation. (Pringle, ibid., vol. I, p. 107)
Under the word "brethren" the Hebrews include all cousins and other relations, whatever may be the degree of affinity. (Pringle, ibid., vol. I, p. 283 / Commentary on John, [7:3] )Huldreich Zwingli:
I give an example: taught by the light of faith the Christ was born of a virgin, we know that it is so, that we have no doubt that those who have been unambiguously in error have tried to make a figure of speech of a real virgin, and we pronounce absurd the things that Helvidius* and others have invented about perpetual virginity. “Friendly Exegesis, that is, Exposition of the Matter of the Eucharist to Martin Luther, February 1527,” in Selected Writings of Huldrych Zwingli, Volume Two, trans. and ed. by H. Wayne Pipkin, Pickwick Publications, 1984 p.275. [As Calvin notes above, Helvidius was the 4th C. heretic who rejected the perpetual virginity of Mary. Zwingli calls Helvidius' opinions "absurd".]John Wesley:
"The Blessed Virgin Mary, who, as well after as when she brought him forth, continued a pure and unspotted virgin." (Wesley, Letter to a Roman Catholic, 1749)
No verse of Scripture identifies any of Joseph's biological children or of any cousins of Jesus.
2. Unless all of his siblings predeceased him (unlikely), a Jesus with younger brothers or sisters commits a sin from the cross in John 19:26-27, by relieving them of their obligation under Torah to support their mother
Only John was present - no other Apostle, or the brothers who "didn't believe in him".
3. Here are some opinions of sola Scriptura Protestants, who may have known their Bibles even better than Matt Slick (!!) on the subject:
Opinion is not necessarily fact.