Sriram,
I have no idea. Just because something is studied scientifically doesn't make it an exact science.
Or indeed studied scientifically:
In an article in Skeptical Inquirer Angel examined Stevenson’s Twenty Cases Suggestive of Reincarnation (1974) and concluded that the research was so poorly conducted as to cast doubt on all Stevenson's work. He says that Stevenson failed to clearly and concisely document the claims made before attempting to verify them. Among a number of other faults, Angel says, Stevenson asked leading questions and did not properly tabulate or account for all erroneous statements. Angel writes:
"In sum, Stevenson does not skillfully record, present, or analyze his own data. If a case regarded by Stevenson to be among the strongest of his cases — the only case of 20 that had its purported verifications conducted by Stevenson himself — falls apart under scrutiny as badly as the Imad Elawar case does, it is reasonable to conclude that the other cases, in which data were first gathered by untrained observers, are even less reliable than this one."[31]
Skeptics have written that Stevenson's evidence was anecdotal and by applying Occam's razor there are prosaic explanations for the cases without invoking the paranormal.[32] Science writer Terence Hines has written:
"The major problem with Stevenson’s work is that the methods he used to investigate alleged cases of reincarnation are inadequate to rule out simple, imaginative storytelling on the part of the children claiming to be reincarnations of dead individuals. In the seemingly most impressive cases Stevenson (1975, 1977) has reported, the children claiming to be reincarnated knew friends and relatives of the dead individual. The children’s knowledge of facts about these individuals is, then, somewhat less than conclusive evidence for reincarnation."[33]
https://en.wikipedia.org/wiki/Ian_Stevenson