In this post, we would like to clear up a common misunderstanding of the egg mechanic.
We believe most of you already know this, but just to be safe we will try to clarify this further, thanks to kjomputer aka Scientist.
- When we get the egg, the Pokemon is decided by the server the second you spin a stop or a gym. After that, the server decided which shell (2 km, 5 km, or 10 km) to put on it.
- When the egg hatches, the Pokemon is revealed. The date that we can see on the details page, is the same date when the egg hatched.
This is the reason why Pokemon Go players often think they’ve hatched a Pokemon that doesn’t hatch anymore.
But to clear this up, kjomputer explains, imagine how conception and birth work. Think that conception is when you spin a stop and receive a Pokemon in the egg, hidden. This is when the Pokemon’s genetic makeup is decided, which can never be changed. When the Pokemon hatches, is when birth happens. So this means that the date of its hatching becomes the Pokemon’s birthday.