I heard that the virgin birth was the result of a mistranslation of the word for 'maiden'. Any truth to that?
Belief in the virgin birth is based on multiple Biblical passages, especially the one where Mary asks the angel, "How can I be pregnant, when I have never known a man?"
You're probably thinking of Isaiah 7.14.
Therefore the Lord himself will give you a sign: The virgin will be with child and will give birth to a son, and will call him Immanuel.
The word usually translated as "virgin" is the Hebrew word "almah." Almah can mean "virgin" or "young woman," somewhat like the English word "maiden." In 250 BC, Jewish scholars in Alexandria translated the Hebrew scriptures into Greek (the Septuagint). For Isaiah 7.14, they used the Greek "parthenos," meaning simply, "virgin." Since these Greek scriptures were commonly used by Jews of Jesus day, Matthew used the word "parthenos" when he quoted Isaiah 7.14 in his Gospel, and claimed it was a prophecy of the way Christ would be born.*
If, however, Isaiah was talking about a young woman conceiving in the normal way, it would not be so clear that the prophecy applied to the Christ. The prophecy also seems to apply to Isaiah's wife, and some Christians believe the prophecy was fulfilled both immediately in Isaiah's wife, circa 700 BC, and later in Jesus Christ. So there's some controversy there.
*I'm no scholar of languages. I'm basing this on various sources I've heard or read over the past few years. Specifically, from
Essential Guide to Bible Versions by Philip W. Comfort, Ph.D., which I just finished reading.