A spirit baby is a soul that is going to incarnate as a new born on Earth but is not in the flesh yet.
Before the soul can incarnate into a tiny human being, there are several stages of preparation until it reaches the spirit baby realm (place of incubation) where it will wait for the divine timing to become as a baby human.
Spirit babies choose their parents, gender, name, religion if any, nation, identity, personality etc. Everything is planned according to the souls' mission and a purpose.
But, like anything on earth plans can change too.
Spirit babies are eager and willing to talk to their parents, but very few humans know that the soul of babies are reachable. it is something rarely heard of before, but as humans are awakening and evolving this is going to become a very simple and normal practice in the years to come.