Natures are inherited from the mother. So if the mom has an adamant nature there is a good chance that the child will be adamant too. Im pretty sure if the mother is holding an everstone it makes the chance of inheriting the nature larger. A good idea is too find a ditto with the nature you want and breed it with whatever you want untill you get teh nature you want.
atleast. thats what i do. Lol :-D
Actually, the mother has no effect on the nature of the baby. Species is inherited from the mother and moves from the father. There are only two ways of affecting a baby's nature;
1. Making one of the breeding pokémon hold an everstone, this gives a 50% chance that the newborn will have the same nature as the one holding the everstone.
2. Using Ditto as one of the parents. Like with an Everstone, the chance of the newborn being of the desired nature becomes 50%.
So the best way to go is using a Ditto with Everstone, that way you have a 75% chance of getting the right nature. :O
Also, in the wild; if your lead pokémon has the 'Synchronize' trait then there's a 50% chance that any wild pokémon you encounter will have the same nature as the synchronizer.
And yes, natures have a significant impact on how a pokémon's stats develop (± 10% to a stat, unless it's a neutral nature), each nature that increases one stat will decrease another, and the effects of the individual natures are:
Adamant (+Atk, -SAtk)
Brave (+Atk, -Spd)
Lonely (+Atk, -Def)
Naughty (+Atk, -SDef)
Modest (+SAtk, -Atk)
Quiet (+SAtk, -Spd)
Mild (+SAtk, -Def)
Rash (+SAtk, -SDef)
Jolly (+Spd, -SAtk)
Timid (+Spd, -Atk)
Hasty (+Spd, -Def)
Naive (+Spd, -SDef)
Impish (+Def, -SAtk)
Bold (+Def, -Atk)
Relaxed (+Def, -Spd)
Lax (+Def, -SDef)
Careful (+SDef, -SAtk)
Calm (+SDef, -Atk)
Sassy (+SDef, -Spd)
Gentle (+SDef, -Def)
Bashful/Hardy/Quirky/Serious (No change)
Also, the stats that natures affect determine a pokémon's pokéblock preferences. Each stat is associated with an attribute. A pokéblock associated with the stat that the pokémon's nature increases will be liked (Meaning the pokéblock will increase that attribute more than usual and the pokémon's liking for you will increase) and a pokéblock associated with the stat that the pokémon nature decreases will be disliked (Meaning a smaller attribute increase and lowering the pokémon's affection) pokéblocks associated with stats that the pokémon's nature doesn't affect will recieve neutral reaction (meaning a medium sized attribute increase and only a small amount of increased affection). Stats and attributes associate like so;
Attack - Coolness
Special Attack - Beauty
Defense - Toughness
Special Defense - Smartness
Speed - Cuteness
And that is all.