How was God born?

This Shabbas during Kiddush an 8-year old had a serious question: how was God born?
Great question ... everything we know in the physical world has a beginning and an end. Even the universe itself, we theorize, began in the "Big Bang" billions of years ago. That is the nature of the material universe - things come into existence, age, and stop existing.
God though (I explained) is different and unique. God is incorporeal, completely spiritual, without the physical that begins and ends. God existed before the Universe began and will exist after the Universe stops (if this is what will happen). This is one of the things that makes God God - God is, outside the physical. This is probably what God's Name, YHWH, means: "I am" or "I am and I will be."
The closest metaphor to understand this is LOVE. For us love exists with a physical source (ex. parents). But when the source of the love dies, the love lives on. My grandparents are gone many years now - but their love is still a part of me and I still feel it powerfully, almost every day. Spiritual qualities exist beyond physical realities - God is the source of this fundamental aspect of life.
No one truly understands what God is. But we do experience God because we also have a spiritual side to our minds. When we say that God is ONE (Shema Yisrael) we are affirming that God has no parts, no physicality and that because God is spirit - God truly is ONE.