One primary putative evidence for reincarnation is the recurrence of birthmarks that correspond to the decedent. For instance, Ian Stevenson, a leading apologist for reincarnation, stresses that line of evidence. With that in mind, here's an interesting story:
Meet baby MilliAnna, the fourth generation of women in her family to be born with a wild streak of white hair.
The 18-month-old, from Ridgeland, South Carolina, was born with a unique birthmark that leaves a patch of her dark hair bleached white — just like the previous three generations of women that came before her.
The trait was passed down from her great-grandmother Jaonne, 59, to her grandmother Jennifer, 41, to her mother Brianna, 23. Now, MilliAnna is the latest to be born with the extraordinary hair.
By reincarnationist logic, this means the same decedent simultaneously transmigrated in four living individuals! How one person can be reincarnated as four coexistent people poses quite a metaphysical conundrum for personal identity. Put another way, this goes to show that sharing a distinctive birthmark is unreliable evidence for metempsychosis.
Indeed, I daresay it's statistically inevitable that in a world with billions of humans, some unrelated people will share common birthmarks. That's a natural, predictable coincidence.