You should ask yourself the inverse. Why would you want to come back in the first place? Many religions go to great lengths to make sure the deceased DNA is destroyed forever. And why keeping samples of people like hairs, body parts and skeletons is considered taboo. Even photographs.:)

May there be some truth to it? Do the ancients know something we don't? The only truth is that we simply don't know. And the more we know, the more we are sure about that, as the book on quantum entanglement is only just opening...

But, on the other hand, storing your newly born children's stem cells today does make sense. By the time they grow up stem cell therapies will certainly have evolved rapidly and, if they can afford it, will improve their quality of life. Seems to me a far smarter investment of your current funds:)