Alpha Protocol, thinks that human interaction is a very important element in RPG -- especially when it comes to the love shared between two consenting adults. Avellone recently commented to Destructoid that including sex scenes in Alpha Protocol was "an important step, and it's not sex for sex's sake, but it's part of human interaction that makes you more involved in the game world and your characters."
Sometimes the act can come off more out-of-place than appropriate, which our time with Dragon Age: Origins seemed to highlight, but, on the other hand (keep it where we can see it!) the sex scene in Mass Effect was fairly tasteful. Well, unless you're one of the misinformed minds at Fox News.