In my belief, it's random what teenager you get.
For kids, if the previous adult had full discipline, you'll get Kinakomotchi, Kuribotchi, Kuchitamatchi or Mohitamatchi, depending on which version you have. Kinakomotchi is for v1, Kinakomotchi and Kuribotchi for v2 and Kuchitamatchi and Mohitamatchi for v3. If the previous adult did not have full discipline or you just hatched a Tamagotchi, version 1 will have Marutchi, version 2 will have Marutchi or Hotodetchi and version 3 will have Mizutamatchi or Tamatchi.
In some people's opinion, if you get a Tamagotchi living to an adult, you're good. If you get a Mametchi/Mimitchi, you're better. But I am fully fed up with Mametchi/Mimitchi, so I'm aiming toward other characters.