Short answer: It does not matter. The only thing that matters is that people act as if they did.
A “womb” in Hebrew is the same word as “mercy.” But the word for “womb” in Greek is the root word for “hysteria.” Greeks and Jews share the same definitional biological understanding of a woman, but while Hebrew emphasizes the feminine qualities of sensitivity and empathy, the misogynistic Greeks chose to define women by the flip-side of sensitivity: volatility. The perspective we choose, the stories we tell, matters.
There is a reason why, even before the people leave Egypt, G-d tells us, no less than three times, how to tell the story in the future! Because every event can be told an infinite number of ways – the way we choose to interpret – to tell – events, defines what we learn from that collective memory, and helps define our path going forward.
The Jewish people are defined by the Exodus; it is a constant reminder in the text. That is our story, and it has kept us for over 3,300 years. Telling that story every year on Passover is what keeps the story alive.
Similarly, Christians believe that Jesus lived. And while I am quite sure that the “facts” matter to both adherents and critics, they don’t matter to me, because I am keenly aware that what really matters is what people believe.
Our beliefs lead to our words and actions and deeds. And it is those deeds, not whether the founding beliefs are mythical or factual, that are the measure of any person or society or civilization.