Soft Reset Method
This method is based on the fact that in Emerald, Diamond and Pearl, gender, nature (personality) and ability (trait) are already set (locked) as soon as the egg is created, before you take it. That means that if you save exactly before taking the egg and then soft reset, the Pokémon inside the egg will have the same gender, nature and ability if you load again.
- Save in front of the Day Care man.
- Take the egg.
- Bike on the breeding route.
- Ignore the next egg proposed to you by the Day Care man.
- Hatch the egg.
- Check the newly hatched Pokémon to see whether it does have the desired gender, nature and ability and
- If it doesn't have the desired gender/nature/ability, save in front of the Day Care man again (there should be another egg waiting for you, which was produced while you hatched the first one) and repeat the process until you get a suitable baby.
- If it does have the desired gender/nature/ability, but it doesn't have the desired IVs, soft reset the game (START+SELECT+A+B) and take the egg again (gender/nature/ability won't change, only the IVs), hatch and check the IVs, repeat the process until you get the IVs you want.
Pros:
- The gender, nature and ability you want are set in stone.
- This method is useful to get a female Pokémon with the right nature and a few perfect IVs.
- It is also useful if the parents don't like each other much.
Cons:
- Not many babies are bred and checked using this method, which means that it can get hard to get the right IVs when there isn't a high probability.
- This method does not suit persons who care about game time more than anything else.
It is recommended that this method is used in the beginning, when the probabilities to get the IVs you want are still relatively high (like when getting 1 or 2 flawless IVs). Alternatively, you can use this method when you're trying to get a female parent with the right nature. If you want to breed for 3 flawless IVs or more, where the probability of getting the desired IVs is less than 1 in 50, the running method is recommended.