You can choose to have a romance or not in any & all Bioware games, it is up to you. However, unlike other companies, Bioware have found the perfect way to attract female gamers by making romance options available in their games.
The pivotal part of the game, DA: Origins, is not to have sex; it is to save the world from this thing called the Blight. You can then choose to have a romantic interest that may or may not lead to you having sex in the game.
If someone buys the game thinking it is going to be a sex-simulator, they will be greatly disappointed; other games or sites for this sort of thing there are on this new fangled thing called the internet....
On a more general note, my hopes for this game, DA: Origins, actually went a little up when I watched this hands-on demo, especially since it featured some of the most intriguing dialogue, I have seen in a crpg for a very long time.