Pokémon breeding
Pokémon breeding is a method of making a new Pokémon by producing and hatching a Pokémon egg. In the anime, it also refers to Pokémon grooming and caretaking.
In the games
How to breed
Pokémon can be breed by leaving two compatible Pokémon at the Pokémon Daycare in Generation II and beyond, located on Route 34 in Johto, Route 117 in Hoenn, Four Island in the Sevii Islands, and Solaceon Town in Sinnoh. Two Pokémon are compatible if they are of the same species and opposite gender, share at least one Egg Group (see below), or one of them is Ditto. Legendary Pokémon (except for Manaphy) and baby Pokémon cannot breed. Pokémon with gender unknown (besides the aforementioned legendaries) can only breed with Ditto. After returning to the Daycare, the old man will be outside (Generation II), out of line with the fence (Generation III), or facing the road (Generation IV). The man will hand the player an egg, if he or she replies to his question with yes. After walking around for a while, the egg will hatch into a level 5 (Generation II and III) or level 1 (Generation IV) version of the bottom of the female's evolutionary chain.
Examples:
| Ditto breeding | ||||
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| Metagross | + | Ditto | = | Beldum |
| Same species breeding | ||||
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| Weezing♀ | + | Weezing♂ | = | Koffing |
| Same evolution family breeding | ||||
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| Charmeleon♀ | + | Charizard♂ | = | Charmander |
| Same Egg group breeding | ||||
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| Raichu♀ | + | Wigglytuff♂ | = | Pichu |
However, there are two pairs of Pokémon species where the male and female are treated as different Pokémon. In these cases, the egg may hatch into either the male or female species:
There are also some Pokémon which will produce variable eggs. The Pokémon that is in these eggs will depend on whether or not the parents held a certain type of held item, an incense.
| Parent | Holding | Child | |
|---|---|---|---|
 Marill |
 Azumarill |
File:SeaIncenseSprite.png Sea Incense |
 Azurill |
| Nothing | Marill | ||
Other Pokémon like this include Wobbuffet in Generation III and beyond, and Roselia/Roserade, Chimecho, Sudowoodo, Mr. Mime, Chansey/Blissey, Snorlax, and Mantine in Generation IV and beyond. Each requires a different attached incense to breed the baby form.
Hatching eggs
The time it takes for eggs to hatch depends on the species. Magikarp is the fastest hatching Pokémon. Some baby fairies, such as Cleffa, Pichu and Igglybuff hatch quickly as well. Besides these, most Pokémon take considerable time to hatch. Rare and powerful Pokémon, like Dratini, Bagon, Beldum, Larvitar, Aerodactyl, Snorlax, Chansey and Eevee, among others, take a long time to hatch.
"Time" is actually determined in steps. For example, a Gligar takes 6364 steps to hatch. Therefore, riding a bike would reduce the egg's actual hatching time by travelling quickly. Pokémon Ruby, Sapphire and Emerald allow players to use the Mach Bike, which is twice as fast as the Acro Bike. Pokémon FireRed and LeafGreen give players a harder time hatching their eggs, however, for there is no "Mach Bike" available. This was compensated with new egg moves for certain species of Pokémon. Additionally, in Pokémon Emerald, if any Pokémon with Flame Body or Magma Armor is in the party, it reduces the hatching time by half: A Gligar egg would take only 3282 steps if a Slugma is in the party. This feature became standard Generation IV.
Passing moves down
The moves obtained by a Pokémon when hatching are as follows:
- The Pokémon will start with any moves that it would learn at a level of 5 or lower.
- The Pokémon will start with any moves that it would learn by leveling up only if both parents know the move.
- The Pokémon will start with any TM or HM moves that the father knows and the baby can also learn by machine.
- The Pokémon will start with any Egg Moves that the baby can learn and the father knows.
The moves will take precedence in the order listed, and if there are more than four moves to learn, the moves will start being overwritten much like when leveling up at the Pokémon Daycare.
Inheriting stats
A Pokémon's Individual Values are also passed down. This is determined differently between Generation II and Generation III games.
Generation II
In Generation II games, the baby inherited its stats from the parent of the opposite gender, unless one parent was Ditto, and in that case it would inherit the stats from Ditto. The Defense IV (Individual Value) is passed, and also either the Special IV or the Special IV plus or minus 8 (plus for values in the 0-7 range; minus for values in the 8-15 range); the Special IV has a 50% probability of remaining the same. Attack and Speed IVs are determined entirely at random, whereas HP is determined by the IVs of the other four stats, using the same formula for wild Pokémon. The probability of a Pokémon inheriting all of its opposite-gender parent's IVs is therefore 1/512.
When determining if two Pokémon are compatible, their egg group is only one criterion. For Pokémon of the same egg group, if the Defense IVs are the same, and either the Special IVs are the same or 8 off, they are incompatible. This is due to the high likelihood of a family relation, hence the inability to breed.
Generation III
In Pokémon Ruby, Sapphire, FireRed and LeafGreen, exactly three of the baby's IVs are inherited from either parent (which is to say that one parent can contribute a number of IVs that ranges from 0 to 3, and its mate will contribute the remaining number of IVs from other stats). The other three are determined at random, in such a way that it is possible that more of the offspring's IVs will coincide with those of its parents.
In Pokémon Emerald, this process is similar but more complicated. First, a random IV is passed from one of the parents to the baby. Afterwards, a random IV of any stat other than HP, is inherited from either parent to the baby. If this IV is from the same stat as the first IV (not necessarily the same IV value, depending on whether or not the same parent passed it on), it will override it. Finally, another random IV of any stat other than HP and Defense, is passed from one of the parents to the baby. This IV will override any of the previous two if it is from the same stat. The remaining stats (a number ranging from 3 to 5) are determined at random, again with the possibility of one or more IVs coinciding with those of the parents.
Another change introduced in Emerald is the ability to inherit Nature, which also influences stats. If the mother (or Ditto) is holding an Everstone, the baby has a 50% chance of inheriting that Pokémon's Nature. When breeding a female Pokémon with Ditto, both of which holding Everstone, it is Ditto whose Nature has a 50% chance of being passed.
Generation IV
Inheriting IVs and Nature in Pokémon Diamond and Pearl is determined in the same way as in Pokémon Emerald. The only minor exception is in the case of inheriting Nature, which is not influenced by Everstone when breeding two Pokémon that do not originate from games of the same language.
Oddities
Some aspects and contradictions of breeding in the games have spawned debate and confusion. Those Pokémon which breed differently whether holding or not holding an Incense are also popularly debated, most especially if the Incense is necessary in the first place to make an excuse as to why the Baby forms could not be previously obtained. Also, some unusual pairings of Pokémon can be found within the Egg Groups, such as Sandslash and Arbok, or Skitty and Wailord.
One particularly unusual note is that Nidorina and Nidoqueen cannot breed, despite the fact that their pre-evolution and male counterparts can. No reason has been given for this.
Another very unusual note is that Seviper and Zangoose can breed, despite the fact that the Pokédex says that they are mortal enemies.
Though there is no way for legendary Pokémon to be bred, there is is evidence that it occurs somehow, since eggs with Articuno, Zapdos and Moltres can be hatched in Snap and a baby Lugia has been seen in the anime. Likewise, Manaphy can be hatched from a special egg from Ranger in Diamond and Pearl. Furthermore, Manaphy is the only legendary Pokémon who can breed with a Ditto. However, the offspring will be Phione, who doesn't evolve into Manaphy.
When a Pokémon hatches from an egg during both Generation II and Generation III, it is at level 5; however, Pokémon can be found in the routes around the player's hometown that are leveled lower than this, down to level 2. This oddity was addressed in Generation IV, where all hatched Pokémon started at level 1.
No negative effects occur from inbreeding Pokémon in Generation III and Generation IV, despite this being impossible in Generation II.
In the anime
In the anime, Pokémon breeding refers to an entire line of work practiced by Pokémon Breeders, such as Brock. So far, the anime has shown and discussed little about the literal breeding of Pokémon to produce eggs, but it is assumed this is part of a Pokémon Breeder's work.
Pokémon breeding in the anime focuses heavily on raising healthy Pokémon and keeping them in top condition by grooming them well and feeding them nutritious food.