Apple's ResearchKit has only just been announced, and most agree that the project has tremendous potential to improve medical research. Being able to tap anyone with a smartphone as a potential low-time-commitment research participant could make research trial recruiting cheaper, easier, and lead to larger, more representative samples.

But will ResearchKit be able to tap anyone with a smartphone, or just anyone with an Apple device? As Dan Primack wrote in a recent Fortune editorial, on a global scale Android is the more popular platform. And the technology can be of a bigger benefit to medical research if it can be used by anyone, regardless of smartphone platform.

The truth is, whether the platform will work with Android phones is still an open question. The API won't be available for another month. So far, the five apps that have been released have been iOS apps, and the scope of their research is limited to Apple users. John Wilbanks, the Chief Commons Officer at Sage Bionetworks, which worked on two of the five initial apps, said that right now those apps work on Apple phones for logistical reasons.

"On a pragmatic level, there’s not very much variation among the sensors between those three [iOS] phones," he said. "The gyroscopes, the accelerometers, the GPS; the chipsets are pretty much the same. That makes it pretty easy from a scientific perspective to normalize the data. When you get to the Android thing, a big part of the challenge is going to be normalizing across different hardware devices."

In addition, some of the apps integrate with Apple Health and Apple HealthKit, which could make an Android integration even more challenging. Other companies working on similar products also start with just one platform, because of those logistical issues. Kibby McMahon, cofounder of PocketLab, said their experience is very similar.

"The first phase is really to figure out what product is going to be, to make it the best and the most flexible, and then to build in Android," she said. "But for right now, there’s enough people with Apple phones. The downside is that we’re getting a very specific group of people that would be able to participate. Android is definitely the next phase, and we talk about that a lot, once we bring PocketLab up to a stable point."

Wilbanks thinks it will really depend on how badly developers -- and, by extension, doctors and researchers, want the integration.

"The whole point of open sourcing something is that if someone wants to do an Android port, that’s ok. That’s what open source is about," he said. "The real question will be how many people who come to the community want that? ... I think in order for it to work for Android there’s going to have to be a community of developers who are willing to dig their hands into the code and make it work on Android. And we just don’t know until it gets out there how hard it’s going to be."