If Mary is "Blessed among women" she MUST be in all ways superior to every woman ever. So she must be superior to Eve who was created free from sin -- the Mother of God MUST be superior to the mother of Cain.
And if Mary did have other children, why is there no mention of them in scripture?
Matthew 13:55 (KJV)
55 Is not this the carpenter’s son? is not his mother called Mary? and his brethren, James, and Joses, and Simon, and Judas?
So Jesus had 4 brothers. Why would you say that Mary didn’t have any more kids afterwards?