Generations is a function first introduced on the Mesutchi and Osutchi, and has since become a standard feature as of the Tamagotchi Connection, appearing in almost every release since. It is a factor used primarily to keep track of the Tamagotchi's family history.
When a Tamagotchi is started for the first time, it will start from generation one. The generation counter resets if a Tamagotchi dies. Manually resting the entire game resets the counter as well. The game Generation numbers always cap at 99, though the player can raise more than 99 generations. Each generations lasts between five and seven days on average, and the next generations begins after Marriage. The current generation number can be viewed when using the Meter icon. On the Mesutchi and Osutchi, it has its own icon (along with TMP).
A Tamagotchi's current generation number, depending on whether it's an odd or even number, may determine what characters it is capable of becoming. This function was introduced on the Tamagotchi Connection, and was reused for the Version 2, Version 3, Keitai Kaitsuu Tamagotchi Plus, Keitai Kaitsuu! Tamagotchi Plus Akai, Tamagotchi Music Star, Tamagotchi Plus Color, and Hexagontchi.
On the Tamagotchi Connection Version 5 and the Tamagotchi Connection Version 5 Celebrity, when the user chooses to marry their Tamagotchi characters, up to three eggs can be produced, (with the exception of marrying Sunnytchi or Jeweltchi, which always produces one egg). From the second generation onward, the parents obtained in the previous generation will appear in several animations.
On the Tamagotchi Friends, the gender of the baby is relevant to the egg chosen. Both babies can be obtainable from all three eggs, and which baby hatches in the first generation is random; however, what baby hatches in subsequent generations depends on which egg was chosen. The egg chosen for the first generation will be hatched for all following generations.