It's not mistranslated at all. The Hebrew word in question, almah, can mean either a young maiden (which in those days were assumed to be virginal) or an actual virgin. The translation then would be determined by the context. Let's look at that. I will place the word almah where it should be. Isaiah 7:14 Therefore the Lord himself will give you a sign: The almah will be with child and will give birth to a son, and will call him Immanuel. Now, if this simply means maiden, (married or not) how would this qualify as a sign from god Himself? Thousands of young women would have been pregnant in Israel at any given time. Which one of them would qualify as a sign unto Israel? Virgin fits better, because of at least 4 reasons. First, a virgin birth would truly be a sign! Secondly, the angel Gabriel announced the birth of the Christ child to a virgin named Mary. Thirdly, the New Testament translates Isaiah 7:14 using the word virgin: Matthew 1:22-23 So all this was done that it might be fulfilled which was spoken by the Lord through the prophet, saying: Behold, the virgin shall be with child, and bear a Son, and they shall call His name Immanuel, which is translated, God with us. Fourthly, Genesis 3:15 prophesies that a Redeemer would come through the seed of a woman- not through a man. The only way that could happen is through a virgin birth. Fifthly... well let's go to another quote first... Well of course there are; Satan loves to twist God's truth. The idea of the virgin birth of the Redeemer precedes all human literature. How do I know that? God wrote it in the stars! The constellation Virgo is a virgin, and that is where the true zodiac begins. The brightest star in Virgo is Spica, which means "branch". Go to a star atlas, and you will see Virgo the virgin shown holding a sheaf of wheat, where Spica is located. What is the significance of Spica? No less than 6 times in the Old Testament, the coming redeemer was referred to as the "Branch" (capitalized, especially in the King James version). Isaiah 4:2 In that day the Branch of the LORD will be beautiful and glorious, and the fruit of the land will be the pride and glory of the survivors in Israel. Isaiah 11:1 A shoot will come up from the stump of Jesse; from his roots a Branch will bear fruit. Jeremiah 23:5 "The days are coming," declares the LORD, "when I will raise up to David a righteous Branch, a King who will reign wisely and do what is just and right in the land. Jeremiah 33:15 In those days and at that time I will make a righteous Branch sprout from David's line; he will do what is just and right in the land. Zechariah 3:8 Listen, O high priest Joshua and your associates seated before you, who are men symbolic of things to come: I am going to bring my servant, the Branch. Zechariah 6:12 Tell him this is what the LORD Almighty says: 'Here is the man whose name is the Branch, and he will branch out from his place and build the temple of the LORD.' Another place that Virgo is seen in Scripture, is Revelation 12:1 Now a great sign appeared in heaven: a woman clothed with the sun, with the moon under her feet, and on her head a garland of twelve stars. In this sense, Virgo is not just Mary, but the nation of Israel. Keep in mind that in the Old Testament (esp. Hosea) Israel was said to be God's wife. So she is clothed with the sun (glory of God), with the moon (the church) under her feet, and a garland of 12 stars (12 tribes of Israel) on her head. Anyway, I don't want to get too off topic here. Suffice it to say, that Christianity didn't borrow any concepts from pagans- it is the other way around!