"Indeed, I was born guilty, a sinner when my mother conceived me" (Ps. 51:5, NRSV). This indicates that the unborn child possesses a sinful, fallen nature at the time of conception (though it does not manifest in actual, personal sins until later; cf. Romans 9:11). Since sin is a spiritual phenomenon, the presence of a sinful nature indicates a spiritual nature and thus a soul, making the child a complete human being from conception.
The Vedas teach the same thing. The soul enters the egg at the moment of conception. With no soul, there is no life. “Life” means “the soul is present”.