You don’t know that she bore other children. as for the titles, one you don’t mention is “Mother of God,” or in Greek, theotokos. “Bearer of God” to the world. By refusing to accept Mary, Protestant risk lapsing into the Arianism to which so many of them are prone, a doctrine that denies true divinity to Our Lord.
Well, scripture says, “Joseph...took his wife, but knew her not until she had given birth to a son.”
It says, “And she gave birth to her firstborn son and wrapped him in swaddling cloths...”
And it says, “And his mother and his brothers came, and standing outside they sent to him and called him. And a crowd was sitting around him, and they said to him, “Your mother and your brothers are outside, seeking you.” And he answered them, “Who are my mother and my brothers?” And looking about at those who sat around him, he said, “Here are my mother and my brothers! “Whoever does the will of God, he is my brother and sister and mother.”
and, ““Is not this the carpenter, the son of Mary and brother of James and Joses and Judas and Simon? And are not his sisters here with us?” And they took offense at him.”
If you want to claim Jesus was an only child, it seems the burden of proof is on you. And FWIW, both Greek and Aramaic had words for cousins or kinfolk.
Oh my gosh. That's terrible. :-)
Nah, don’t worry your little head about us protestants. We most certainly believe in the Trinity and Mary isn’t in it.