An unnoticed "miracle"

Yesterday I was thinking about how we are always individuals, even from conception, even though we go through a period of sharing the functions of our mother's bloodstream. We do not share the blood, just the bloodstream functions. The individual floats up the fallopian tubes and embeds into the uterine lining. The interface between the individual and mother forms; we call it a placenta. Mother, uterus, placenta, umbilical cord, infant. The entire time of gestation the individuals remain separate. Yet there is nutrient and gas exchange across the villi of the placenta, and this exchange enables life to be passed on. If a product of evolution, definitely all the right changes took place at all the right times. If a product of design, how infinitely wondrous the knowledge of detail. But who thinks about placentas routinely except those who have to discard them on a daily basis?