Humans beings only have one life: the one that they live. There is no such thing that can be described as a Self which recurs from one birth to another. Reincarnation and rebirth is limited to the obvious scientific fact that the materials that that constitutes one in terms of atoms have been recycled in Nature for perhaps millions of times through evolution of animals. This is because the sperm and egg that fused to make a person came from parents who likewise came from their parents sperma and eggs etc. The food one eats also gets recycled through the soil and waterways of Nature in another way. However, even if the precise atoms that makes ones body may not have been in the bodies of ones ancestors for more than a few generations previously, the DNA that constitutes the body does have a close relationship with that of organisms for perhaps hundreds of millions of years or even up to the 3.5 billion years of life on Earth, so that the DNA and RNA have in this way continuously reincarnated with modifications through these generations in the paleontological tree of life.
Some humans believe that they have existed in previous lives. This is the normal meaning of reincarnation and rebirth in religious terms. It has no basis when the science is considered. The consciousness energy of the universe does not have any means for the transfer of this information through successive rebirths. So does this mean that people who report memories of events in their previous lives are deluded? Yes, any such thoughts would have to be planted into the minds by guna consciousness deities to control the individual. Thoughts and visions can also be planted into the mind by God himself for whatever reason through the guna consciousness energy process.