Gen 2:7 And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.
It appears that the soul is created when a baby breathes on his/her own...
My son was born prematurely and needed to be on the ventilator to breathe.
Psalm 139 -
13 For you created my inmost being; you knit me together in my mother's womb.
14 I praise you because I am fearfully and wonderfully made; your works are wonderful, I know that full well.
15 My frame was not hidden from you when I was made in the secret place. When I was woven together in the depths of the earth,
16 your eyes saw my unformed body. All the days ordained for me were written in your book before one of them came to be.
Where ignorance is bliss, 'tis folly to be wise.
"Before I formed thee in the bowels of thy mother, I knew thee: and before thou camest forth out of the womb, I sanctified thee, and made thee a prophet unto the nations." Jeremias 1:5