That's true, bobad. A baby is very much alive before it is born. Hmm.

Perhaps the first breath was said to mark the beginning of life for a much simpler reason. Childbirth was a much riskier experience for both mother and baby, before recent times. After a baby is born, until it breathes on it's own it's life remains uncertain. And unless it breathes, it dies. So the first breath proves that the baby is indeed viable.