Ken frowned. It wasn't all that bad losing height, but becoming younger worried him. How long would the process go on? If Mike was a good judge, he already looked like a young kid.
"We gotta check in with the doctor. He can tell us what's going on."
***********
The fact that the doctor wasn't surprised when they walked into his office an hour later told them a lot. He had them sit down. "Sorry I didn't warn you about the effects, but I didn't want to bias the results. You see, the injection activated several processes. One made you more muscular, better developed. The other adjusted your body to compensate for redistribution of mass.
For people who are overweight, there is no change but the muscle. You two were trim and healthy, with almost no fat to convert. So the seconday process searched your genetic past to find a form that better fit the new physical pattern being forced. Obvously, you both ended up younger."
Mike frowned. "So, it will stop now, right? And we'll grow up again?"
The doctor sighed. "Well, it depends on how much muscle you develop. You are both very defined now, like well-trained swimemrs or runners. If your muscle type changes to something more like a football player, you'll both end up losing more years. It will stop when you reach what the process determines is the right build."
Ken stared. "You mean we could end up a 13 year-old jocks?"
The doctor nodded. "I'd say that's the youngest you'll get."
"What about growing up again?" Mike glared at the doctor. "You didn't asnwer that part."
The doctor shrugged. "We don't really know at this point. It takes weeks to determine if someone is aging. There is a chance you are both permanently kids."