Yes.
i don't know about a code but in Sapphire my treeko was a girl so i think it is luck
Just breed your starter (It SHALL be a girl, with one of the same egggroup -_-' Or you can breed a Pokemon (No matter what gender is it, just do it!) with a Ditto, and then you will get a egg by the starter!
They aren't. If you tell them you are a girl, your starter will be a girl.
As many as you can get
The rival in Pokemon sapphire, ruby and emerald is brendan or may. It depends if you a boy or a girl at the beginning (boy=May , girl=Brendan).
Save your game before choosing a starter Pokemon keep choosing the same starter until its a female.
You get it from the little girl in slateport city
if you picked a girl as your player then 50% chance your starter Pokemon is a female.
yes it depends on the sex (male or female) if your a male your starter is a girl like mine
Save the game in front of the bag where you choose your Pokemon. Then, choose the Pokemon and when the battle proceeds see if you have a girl. If not, in-game reset (A+B+Start+Select) and try again. It is possible to get a girl this way, as this was how I got one.
trade harbor mail with a girl in mauville
no.