As the problem of the sex scenes within Grand Theft Auto tends to become a nationwide scandal (ABC News has broadcasted a 2 minutes interview with David Walsh from the National Institute on Media and the Family and with the politician that started it all, Leland Yee), the information regarding the HotCoffee mod are beginning to be more and more interesting.
According to the TeamXbox website, the sex scenes also exist in the versions for Xbox and Playstation (Grand Theft Auto has been initially launched for PS2 in 2004), but their activation is much more complicated than in the case of the PC version.
In a comment regarding the HotCoffee mod, Jordan Liles from PlanetGrandTheftAuto says that it's not unusual for GTA to contain certain unfinished pieces of code, Vice City menus still existing in San Andreas.
If ESRB discovers that Rockstar is guilty of inserting the sexual content in the game, than its rating will be changed from M (mature) to AO (Adults Only), which would cause the sales to plummet.
In any case, the Sex in Grand Theft Auto scandal tends also to become an international one, and the Sidney Morning Herald tells us that the Office of Film and Literature Classification from Australia has begun investigating whether the allegations against GTA are real.
If they are confirmed, Grand Theft Auto San Andreas could be banned in Australia.
Besides changing the rating, ESRB's officials haven't said anything yet about any other consequence Grand Theft Auto's developers might suffer.