The Virgin Birth
It was important that Christ be born of a virgin for five primary reasons. First it was a fulfillment of prophecy. Isaiah 7:14 says, “Therefore the Lord himself will give you a sign. Behold, the virgin shall conceive and bear a son, and shall call his name Immanuel.” Matthew shows this being fulfilled in Matthew 1:23. We are told that Mary is a virgin by Luke in Luke 1:27 and by Mary herself in Luke 1:34. The purpose of this prophecy being fulfilled was that it was a sign of both the incarnation and that this was in fact the Messiah. Secondly, a miraculous birth indicated that he was set apart for God’s special plan. We see similar instances of this with other key figures in scripture. The births of Isaac, Samson and John the Baptist were announced ahead of time by God or his angels (Gen 18:10, Jdg 13:3, Lk 1:13). Thirdly, it represented his own purity. This does not indicate that Mary was sinless, but that her own virginity provides beautiful symbolism for Christ being born from someone who had not been defiled. Fourthly, it satisfied a cultural understanding of righteousness. The Jewish people believed that a sin nature was passed on from the man and not the woman. By having an earthly mother but no earthly father it would have indicated to others that Jesus had no sin nature in him. Finally, it points to his dual nature as both God and man. Jesus is both completely human and completely God. By being conceived of the Holy Spirit and born of the Virgin Mary, we see a physical representation of a spiritual reality.
Where Catholics Have Gone Wrong
What Catholics believe is that for Mary to be worthy of giving birth to Christ, she herself had to be sinless. But scripture teaches in Romans 3:23 that all have sinned. This includes Mary. She was special in that she was used by God, but she was by no means sinless. As such, she should not be worshiped or prayed to. God alone is worthy of our worship.