What stat do I increase for a DPH Aegislash

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.

There have been other items like this. In Gen 4 you can get a box from a Team Rocket member that gives you a TM in gen 5. The only thing we can sorta know for sure is that it is some sort of event item but as to what it does we can only guess. It may be a year or two before we know what Gamefreak intends to do with this or it may just be nothing at all.