Here is the key passage from an interview with William and Kati Sacks, creators of the Kindara App:
We actually founded the company because we were looking for effective birth control that wasn’t the pill. Kati had been on the pill for 10 years and she didn’t like the side effects. She introduced me to the fertility awareness method and I was blown away by how little I understood about female fertility. I was actually outraged that I had never been taught how reproduction actually works.
Once we started tracking her fertility signs I learned all about how her body worked and also discovered an added intimacy in our relationship. We wanted to share this with other couples, so we started Kindara out of our own desire to give women and men tools that help them take control of their health, understand what’s happening with their bodies and meet their fertility goals.
Imagine that: “I was actually outraged.” For all that liberals say about the importance of “sex education,” including exposing young children to pornography (it’s so disgusting I don’t want to link but there have been several recent controversies about pornographic lessons in public elementary schools), they don’t actually teach anything about fertility. They make a big deal about kids knowing the “mechanics” and so-called “options” and how to use a condom, but not about fertility or how the purpose of the “mechanics” is to make babies.
Now, as apps go, Kindara is apparently only based upon the Sympto-Thermal Method and I believe costs money. Also, it should be noted that “fertility awareness” is technically distinct from NFP in terms of the moral aspects of marital relations, but it’s still a huge step forward.
If you use Marquette Model, I recommend http://www.myfertilitycharts.com/ and its “Cycle Plus” App. It’s mostly free (if you want to get the info on the “Maximum Fertility Window,” they charge a monthly fee for that, and whether you can see Ovulation dates on the app or have to go the website is a feature that comes and goes. However, so long as you understand the basics, you can get by without the fee. It’s a great app, and all the Apps we’ve tried have had options for charting all sorts of other info, as well. So, for example, a woman with chronic migraines, digestive problems, etc., can charge how they relate to her cycle.