I think we are conceived in sin, except possibly for the most religious among us who are simply obeying what they perceive as the word of God with no other motive.
Certainly we are born into a sinful world, our parents not excluded, but I don’t think there is a clear demarcation between a born and an unborn soul as there is between conceived in sin because of our sinful culture and nature and conceived without sin, as with Mary, and others of course.
Thanks.