Egg Groups

• Pokémon breeding was introduced in Gen 2

  GS
• From Gen 2-6, compatible Pokémon could breed by being left at the Pokémon Day Care
• In Gen 7, this changed to leaving them at the Pokémon Nursery.

Locations

• Gen 9
  SV
  introduced a new method: picnicking with two or more compatible Pokémon, regardless of their location in the player's party or in other players' Pokémon visiting via the Union Circle.
• Breeding mechanics are not present in Gen 1,
  LGPLGE
  and
  LA
• Pokémon are considered compatible if they share at least one Egg Group and are of opposite genders.
• Dittois an exception, as it can breed with almost any Pokémon regardless of gender, including genderless Pokémon.
• Pokémon in the No Eggs Discovered Egg Group cannot breed under any circumstances, and Ditto cannot breed with another Ditto.
• In Gen 2 exclusively, if two Pokémon have identical DEFENSE IVs and their SPECIAL ATTACK and SPECIAL DEFENSE IVs either match or differ by 8, they cannot produce Eggs.
  This hints at a familial relationship due to how IVs are inherited from parents.

Exceptions

• Baby Pokémon represent the first stage of development for certain Pokémon species, maturing into their full forms through evolution.
• A baby Pokémon is classified by these conditions:
  • It's possible to obtain it through breeding
  • It's earliest stage of an evolution chain
  • It's part of the No Eggs Discovered egg group
• At first, baby Pokémon could only be obtained through breeding but starting with Wynaut which is catchable in the wild on Mirage Island in
  RS
  , other baby Pokémon can be caught in the wild from Gen 4 onwards.
• Most baby Pokémon are evolved by having a high enough friendship level
• Most baby Pokémon are produced by breeding the adult stage of the Pokémon species while holding an appropriate incense item.
• In some games, the player also receives eggs containing Pokémon.

• A major benefit of breeding is obtaining an egg with a specific moveset
• The egg will inherit moves in the following order
• Any move that the hatched Pokémon knows at level 1 by default
• Any move that both parents know
• Any HM or TM that the hatched Pokémon can also learn (only from the male or non-Ditto parent before Gen 6)
• Any Egg Move that the either parent knows (only from the male parent before Gen 6)
• Volt Tackle if the the parent of a hatched Pichu was holding a Light Ball
• If this order results in more than 4 moves, moves later in the list replace the ones listed earlier

• Starting in Gen 5, abilities can be passed down through breeding
• Only the female's ability has a chance to be passed down (or the male's ability when breeding with Ditto)

• If a Pokémon does not have a hidden ability, there is an 80% chance that the bred Pokémon will inherit the same ability as its female parent.
• Otherwise, it will choose the remaining option (which could still be the same ability if the parent only has 1 option)
• In
  B2W2
  Pokémon can only inherit abilities if both parents are not Ditto.
  The egg will has an 80% chance to inherit its female parent's ability (regardless of whether it's a hidden ability)

• In
  BW
  and from Gen 6 onwards, the female parent has a 60% chance to pass down its hidden ability.
  
• In
  B2W2
  the chance to pass down a hidden ability is 80% (male Pokémon can not pass down abilities when breeding with Ditto)
  
• An egg will never hatch with its hidden ability if it was not passed down through a parent

• Usually, a hatched Pokémon's nature is chosen randomly from the 25 possible natures
• If either parent (only the female parent in
  E
  ) holds an Everstone, it will pass down its nature to the hatched egg (chose randomly if both parents hold an Everstone)
• Before
  B2W2
  there was only a 50% chance of the nature being passed down when the parent holds an Everstone