Matthew 1:24 Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife:
25 And knew her not till she had brought forth her firstborn son: and he called his name JESUS.
25 And knew her not till she had brought forth her firstborn son: and he called his name JESUS.(emphasis added)
Yeah, my version doesn't say it this way, but I like yours better for this issue. :) Why would it say "firstborn", if it was impossible that other children were to follow?