CUPERTINO, Calif. — With little fanfare, porn has finally and officially arrived on the Apple iPhone, only to be removed soon after.

It’s an app called Hottest Girls, and it delivers about 2,200 images of attractive women. The difference is that many of the women are topless.

As of this morning, Apple has once again backtracked on allowing adult content into the App Store, having booted the Hottest Girls app in the United States. Users outside the USA can still download the app.

That change — the addition of nudity — sets this app apart from every so-called “adult” app that has come before. Many, many adult companies offered sexy apps that featured scantily clad models, but now that the third version of the iPhone’s operating software includes parental controls, adult apps now seem to be a reality.

Those parental controls kick in as soon as a user downloads the app. Before downloading, the App Store asks the user to confirm that they’re older than 17.

But despite the good news, one adult company will proceed with caution into the App Store. The Score Group specializes in busty content and has already produced an app for the competing Google Android mobile operating system, but the Miami-based company has to date not tried its hand with the iPhone because of the ban on adult content.

Score’s Lio Berlanga told XBIZ that he and his creative team might dive into Apple’s newly adult friendly pool, but not before checking to make sure it’s filled with water.

“[Building an app] sounds a lot more interesting now that it’s allowed, but we’ll want to do more research on it,” he said. “We’ll definitely be more willing to develop an app, but we’ll definitely want to find out more.”

It sounds like the adult industry can only do better than the Hottest Girls app, which got a negative review from Wired.com.

“The application itself is terrible,” tech analyst Charlie Sorrel wrote. “Four photos are shown on screen at once and tapping one will pull a full sized version from the server. From here you can look at it or save it to your photo-roll. There is no slideshow to display a progressive striptease of the same model, so you are limited to one picture at a time before you have to navigate back to the main screen, which shows a lack of understanding as to how a porn app should work. You could of course just use the application for downloading and view the pictures later in the Photos application.”

But despite the weakness of this first adult app, Sorrel noted that the App Store has powerful age-confirmation technology built right into it.

“This is certainly an interesting move from Apple,” he said. “One of the main reasons for not buying porn on the internet (apart from the vast range of free content) is fear that the purveyors will rip you off if you give them a credit card number. With the Apple Store, your stimulation is just an easy, automatically billed click away.”