There is! It's called drip and is a project started by a berlin-based feminist collective iirc.

https://dripapp.org/

Free, open-source, local data only

So why the fuck don’t women just use that?

They probably don't know about it. If I search "period tracker" on Google Play, Drip is in about 40th place in the results. That's several screens down, past a bunch of search suggestions, and the parts where it's open source, on-device, and optionally encrypted aren't clear until I tap on it and read the description.

And you probably can’t even get drip on iPhones.

There's some irony in a comment dealing with people making decisions that are against their interests because they're insufficiently informed speculating incorrectly about something like this when it's easy to check. Drip is, in fact available for iPhone.

Because its effort. We have to get the average person to care about their security and privacy before they will bother using these alternatives. It's much easier for them to download a popular one off an app store and have the data stick with them, than it is to download f-droid, find the right app, make sure its still supported and setup their own data backup.

i'd like to point out that it shouldn't be on women (or anyone) to be on constant guard against attacks on their privacy.

yes, it is the state of the world, but the attitude of your comment is victim blaming.

let's not forget that while we on Lemmy may be aware of the danger of mass surveillance tech, we're not the majority.

snowden told us years ago how fucked everything is, and surveillance has only grown since then. let's not forget that it is not normal that corpo data-mining is the norm (along with included de-facto warrantless surveillance). Even though we all should be better, nobody should have to be as careful as we are.

hell, let's be real. As long as we use a smartphone, we're not being careful enough either.

I get what you’re trying to say, but this is basically just roundabout victim blaming. Women shouldn’t have to worry about whether or not someone is going to weaponize data on their menstrual cycle against them. Yes it is good to lock your door at night, but ultimately you don’t blame somebody for getting robbed just because they didn't lock it. You blame the thief.

Not everybody is as aware of privacy issues as the rest of us. We have to help them, not berate them.

erm, I do use Drip actually. i have used it for over a year now as I didn't want trackers knowing my cycle.

women do use drip. we just don't advertise it, usually.

i have also recommended it to friends who were looking for a more simple app than these google play store ones.

Besides drip, Euki (github) is another option on both the play store and iOS.

Note that both of these options are maintained by tiny teams with limited resources.

Has "if it makes a funny noise I'll shoot the computer" vibes, love it

I tried to talk to my wife about data ownership, opensource, etc. but it's difficult to convey how important it is. She uses Flow. I'm trying to get her to at least try alternatives such as Drip

You need to teach me this skill. Any excuse to get frisky with my wife.

Would the cops come beating my door down claiming I had an abortion? 🤔

I don't think that has happened starting from a period tracking app yet. There was a case involving an unencrypted messaging app used to discuss a criminalized abortion.

There are 2 open source menstrual trackers in f-droid. They don't share data.