That is roughly 40 million people who have lost physical and mental capacity through the natural aging process.

WSJ: Bionic Brains and Beyond

Participants were under 55 to assure that aging effects were the result of sun exposure, not the natural aging process, Dr. Green said.

WSJ: Sunscreen Each Day Stops Wrinkles

As men in their early 30s continue to sign 10-year, nine-figure deals, everyone from GMs to agents to the players themselves has to believe that the natural aging process no longer exists, or can be beaten.

WSJ: Teixeira Knows His Limits