When can you trade in Pokemon X and Y

So far that I've found, the in-game trades are as follows:

• Bunnelby -> Farfetch'd: Santalune City (House, West from the fountain)
  • Jolly
• Jigglypuff -> Bisharp: Snowbelle City (House, Southwest of the northern bridge)
  • Adamant
• Luvdisc -> Steelix: Cyllage City (Pokemon Center)
  • Impish
• Gyarados -> Magikarp: Random hotel (Must talk to a Hiker repeatedly over the course of a few days)
  • Adamant
• Any Pokemon -> Eevee: Random hotel (Must talk to a woman repeatedly over the course of a few days)
  • Docile and holds a Rare Candy

After Elite Four

• Any Pokemon -> Starter: Vaniville Town (outside your house)
  • You will get the starter yours is strongest against.
• Any Pokemon -> Ralts: Lumiose City, (Cafe Soleil on Southern Boulevard)
  • Comes with Gardevoirite

The gender ratio for the 6th generation starters is currently unknown, but all starters so far had a ratio of 12.5% female / 87.5% male, or 1 : 7.

The gender of your Pokémon does not depend on your character's gender. Both male and female protagonists can have either male or female starters.

This specific gender ratio is used to make it more difficult in breeding more of them since players usually get them as gifts or Fossils rather than catch them in the wild. All starter and Fossil Pokémon are in this group.

The only way to ensure you'll get a female starter is indeed by saving the game beforehand and reloading it as necessary.