Sex in Videogames, well this falls prey to sex in any other kind of media, our largely victorian attitudes to sex have their roots in Christianity, prior to the Christian "re-education" of the globe sex was viewed entirely differently in most cultures, though there was a much wider variety of views on it.
In much of Roman architecture for example there are clear depictions of sexual acts, but the Romans were by no means alone, sex was a out in the open kind of topic & in my view had a far healthier attitude towards it, something sexual health experts can tell you is how much easier it would be to educate, treat & prevent sexual diseases if our attitudes weren't so repressed.
Getting back to games, well until sex becomes more widely accepted as part of society's mainstream then the attitudes to it being in games wont have a hope in hell of changing, whilst sex in films is largely acceptable, though preferred if it is relevant to the story being told, a videogame is interactive & not merely a passive experience & that makes it a thornier topic to deal with, watching a cut scene of sexual behaviour, however explicit, is the same as a film, passive....however add in videogaming elements such as the manipulation of those scenes, & you open a unique can of worms, it's one thing to win a strip poker game, another to actively play a character's role in a complex seduction scene & have an outcome based upon how successful you were at carrying out all of the things the game asked you to do, or made available for you to do, a gaming element whereby you were manipulating your character in order to elicit a response from the other (or even others) characters in the scene/scenario, whether this was done via multiple choice question & answer methods, correctly choosing a path through prior parts of the game, directly manipulating the character via the keyboard, & then taking it as far as current tech allows, "touching" your intended sexual partner(s) by use of peripherals such as the Wii controller......
It's actually a bold largely uncharted frontier, someone will cross it at some point, I agree with earlier posters that any sexual content in a game should fit the story, but whether the world is ready for that yet is another matter, it could be done today, but it is subject to the same things that affect sex in any other media, some of it will be tasteful & thoughtfully done with a sensitivity & tenderness, some of it will be brutal & uncompromisingly animalistic & some of it will be unashamedly gratuitous.
But attitudes to sex, especially in the west are very hypocritical, it's ok to enjoy it, but it's also noy ok to talk about it let alone display it, most everyone does it, but it's perceived as a corrupting evil power more & as many pointed out, it seems strangely more acceptable to blow someone's face off with a shotgun than to try to get lucky with the hot woman/man in the corner of the bar, or with your sidekick that you just came through a wild adventure/horrific experience/alien slaughterfest with.