I think that to be fully human, to experience all there is to be fully a conscious and evolved human that it would be necessary to return many times. How that mechanism works is still a mystery but I think it would be likely that we return to experience what it is like to be male, female, different ethnicities, religions, historical time frames, professions, etc. There may be no scientific way to prove it because it is beyond our ability at the present time but so many people have experienced bleed throughs to past lives and there is so much historical writings about such experiences that to dismiss them off hand seems a little closed minded.
I was born in Montreal to middle class British parents, lived in suburbia, worked as an engineer, then one day I just left all that behind and moved out into the bush in BC where I squatted in an abandoned tool shed from a defunct placer mining operation. I never felt comfortable living in the city but when I moved out into the bush, I felt instantly that that is where I belonged. I instinctively knew how to survive out there. It just all felt so familiar and comfortable.
I was raised Catholic but it never sat easy on my mind. It never made sense to me even as a young child, but when I looked at native spirituality, it just fit me like a glove. It just felt so familiar, so right, like I had come home not only to the forest but to my culture. Aboriginal people accepted me as a kindred spirit right from the beginning. It is hard for me to not think that all that has to do with who and what I was before taking on this shell.
From the people I have met and the interactions I have experienced I would not say that we keep being born into the same family groupings, but more likely the people close to us in life are people who have been close to us in the past, as friends, lovers, sons and daughters, but we do keep changing roles within a close circle of relationships. Even people who are on the fringes of our awareness now could have played a more significant role in the past.
I trust my intuition more than my intellect in such maters. The intellect is limited in its scope. But the intuition is aware of everything that is going on around it, even what is coming at it. That is why some people have avoided catastrophe by being late or because of circumstances seemingly beyond their control. To me science is limited to and by the intellect.