Setting: Alt-reality, futuristic America. MCs are currently in a high-tech version of the Internet which allows the user to experience things on a realistic virtual reality scale. However, with aliens, magic, and even higher, unknown-to-us tech being ushered in, this virtual reality has become a testing ground for the Big Bad so they can usher reality-bending into the MCs real world. This would include rewriting in how biology, psychics, energy manipulation, etc. would work (basically, it would allow for superpowers). Most of the MCs accept these explanations at face-value, but the resident doctor in the party's not as forgiving.
His powers center around ageshifting (he goes from being a late-40s man to a 14-year-old, but can't move into being any younger or older than that). Since this is currently virtual reality, he's not as displeased as he might be should it move into his reality. I'm not planning on having it do so, but:
1. I need some semi-realistic explanations on how age-shifting might work. Just loose theories that are more technobabble than anything else, and I'm not looking to have it tested in the MC's real world. This is more the MC running scenarios through his head on how reality/biology/whatever *might* be manipulated to accommodate these changes. I could handwave it all if necessary, but was looking for something a little more in-depth for Dr. Science MC to freak out about. :)
Edit: Thanks, I think I have what I need to get started.
Thanks for any help!