I believe children are much closer to the world of spirit than we are, because they've just arrived from there and still get glimpses of it.

My DD1 astounded me at a very early age by talking all about my (decreased) Nanna and describing a dressing gown she sewed for my sister when we were little children, "before, when I was the grown up lady and you and aunty kaaren were little girls..." To this day I believe she was talking about her previous incarnation as my grandmother! Just waiting to hear what treats DD2 tells us once she's talking.

Good luck with your scan, can't wait to hear all about it. Perhaps your son is sensing his future brothers and sisters who are still in spirit?