An all powerful God can come into this world in human form any way he wants to.that's why I consider you ignorant of Christian beliefs........a non divine Christ may be sufficient for an atheist, but divinity is fundamentally necessary to Christian doctrine
The Virgin birth narrative is only briefly mentioned once in two Gospels. And never comes up again.
John, Paul, Mark, Peter, James don't mention it.
If the virgin birth was so important, why do the other NT writers not seem to know anything about it?
There are Christians who do not take literally the virgin birth narrative, so you'll have to revise your two billion number downward.
Historical truth doesn't depend on what you believe