Because,Jesus is the Son of God and MAry-the Catholic Church and countless Popes have declared by the Bible an theology,also by the very words of the Virgin Mary,on the Feast day of the IMMACULATE CONCEPTION--it is understood without questioning ,THAT GOD granted MAry the singular GRACE and favor that she was to remain forever a VIRGIN and still bring forth Jesus---this was NOT impossible for GOD-it was HIS will and it was so>
If Mary was "forever a virgin," how does one explain the other children she and Joseph had? Like, say, the Apostle James?
Mary had two other sons. Just because some Italian in a dress says otherwise doesn't make it so.