Reincarnation is a very old belief and a large fraction of the world population believes it. For example Rene Descartes' statement "What I have said is sufficient to show clearly enough that the extinction of the mind does not follow from the corruption of the body and also to give men the hope of another life after death." in 1641 confirms his belief in reincarnation. About 20 percent of those in the Western World whose religions shun reincarnation nevertheless believe it. According to opinion polls this percentage is rising. A science minded person often finds it difficult to accept reincarnation because he/she had failed to perceive a reincarnation mechanism that is intelligible within the outdated Decartes' classical science frame work. But Modern Science, specifically Quantum Mechanics, has compelled us to accept unintelligible mechanisms of natural phenomena like the behaviour of electrons and we do not hesitate to accept them. Likewise with the data available we are compelled to accept reincarnation as a reality. Austrian Scientist Rudolf Steiner says, "Just as an age was once ready to receive the Copernican theory of the universe, so is our age ready for the idea of reincarnation to be brought into the general consciousness of humanity"

Gene at work

This is not even reincarnation just people who look alike

Have you heard about people who were dead, and comes back again and remembers their old lives about where they were living, their husband/wife and kids

Or a little child who for some inexplicable reason 'knows' things she ought not to know.
As soon as my niece was able to walk she would go to the toilet herself (not potty, adult toliet) and struggle to climb it. When she could finally use it she would even flush. She knows to wake from sleep and not wet the bed. She graduated from breastmilk to adult food, no cerelac or any of that stuff. The one that was bought for her was given away. Her elder sister had to be taught all those things.

And no she didn't learn from observation, her elder sister still wets the bed and I daresay a toddler doesn't know what a lavatory is talk less of using it. She refused her potty outright despite watching her elder sister use it.

Also she learned to eat by herself first and button her clothes first. Little little things like that. It makes me wonder.