The point is well known to biblical scholars and not disputed by them. The Hebrew word in Isaiah is ‘almah’, which undisputedly means ‘young woman’, with no implication of virginity. If virgin had been intended, ‘bethulah’ could have been used instead (the ambiguous English word ‘maiden’ illustrates how easy it can be to slide between the two meanings). The translation occurred with the pre-Christian Greek translation known as the Septuagint rendered ‘almah’ into παρθενος (parthenos), which really does mean ‘virgin’. Matthew (not of course the apostle and contemporary of Jesus, but the gospel-maker writing long afterwards), quoted Isaiah in what seems to be a derivative of the Septuagint version (all but two of the fifteen Greek words are identical) when he said ‘Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying, Behold a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel’ (Authorised English translation). It is widely accepted among Christian scholars that the story of the virgin birth of Jesus was a late interpolation, put in presumably by Greek-speaking disciples in order that the (mistranslated) prophesy should be seen to be fulfilled. Modern versions of the New English Bible correctly give ‘young woman’ in Isaiah. They equally correctly leave ‘virgin’ in Matthew, since they are translating from his Greek.
~ Dr. Richard Dawkins (born: 1941-03-26 age: 68), The Selfish Gene , endnotes on chapter 2

Matthew, the writer of the allegedly inerrant bible, is caught red-handed lying to make his tale sound more impressive. How can anyone possibly trust that this man did not tell other serious lies is the rest of his account?