Hi, Steven —
John's right on the nose!
The Immaculate Conception, as the Church has officially defined it, happened in St. Anne's body, not Mary's.
Now because our Blessed Mother was born immaculate and never sinned, Jesus was also conceived immaculately in Mary, nine months earlier. We celebrate this on the Feast of the Annunciation on March 25th.
Many believe, as your friends do, because the Church uses readings for the birth of Jesus at the Christmas Masses.
On the Virgin Birth: Mary's birth was not a virgin birth. As John said, Mary's parents, Sts. Joachim and Anne, conceived Mary in the normal way.
Jesus' Birth was a Virgin Birth — a Birth that happened at Christmas.
It means historically we know, as Jesus was being born by Mary, Mary was miraculously a Virgin:
- During, and
- After . . .
. . . she gave birth to the Son of God, Jesus, our Saviour (True God and True Man).
For that reason she is Mother of all mankind, lay people and consecrated religious.
If you are interested, I have other thoughts and opinions on issues related to your question.
They can be found in Mike's Theology Corner here:
I hope this helps,