This whole argument is a chicken and egg scenario. Do companies not market to women because they don't buy games, or do women not buy games because companies don't market to them?
The Mass Effect series has a lot of things that women like: drama, romance, customization, exploration, character interaction, the ability to play as your own gender etc...too bad the marketing for all three games glosses over these things and makes it look like a generic CoD/Gears clone which is something that does NOT appeal to most women. There was one trailer with femshep, yes. However it was online only, most of the trailers featured Sheploo as did all the promotional material, posters, etc...AND this only came out close to the release date of the final game. Years of zero marketing and then finally one trailer...which still made the game look like a generic shooter but this time with a lady! Even if a potential female customer saw the trailer, her interest was piqued by the fact that she could play a woman, and she did research and found out that hey, this is actually a female oriented game series, she may not want to play a game that is already old and dated or come into a series in the last installment and not know what was going on.
Dragon age is a series that would really appeal to women. Don't hide the fact that we can choose out gender and race, that we can have romances, that the game will make us laugh and cry. Don't just show generic Whitedude McStubblechin and make the promos all about combat and explosions. Showcase a bit of everything the game offers, show its' strengths both masculine and feminine.