Some RF breeder claims "not with 100%" accuracy they can pretty much determine their hatchlings to be males or females upon adjusting the temperatures higher for females & lower for males in the incubators, but every breeder has pretty much confirmed with absolute certainty not even them are able to tell a baby hatchling or yearling from just looking at it alone. So new first hand owners of RFs or any other tortoises should stop asking people on how to sex their tortoises before age 4-5 & over already..so never truth pet shop salespersons they lie to sell you more.