When you request a prediction, we send the biological parents’ heights and the formula’s sex selection to our server. We store those inputs, the result, time, and calculation version, linked to a browser visitor identifier and, if you are signed in, your account. Growth journal measurements, dates, and nicknames stay in your browser; they are not uploaded by the tracker.
Saving is your choice
Working records are kept in the open page unless you explicitly enable local saving. With local saving enabled, the application stores the record in that browser’s local storage so it can be restored on a later visit.
Local storage is tied to the same device, browser profile, and site address. It does not sync across browsers or devices. Clearing site data, using private browsing, changing the site address, or browser storage restrictions can make records unavailable. Anyone with access to the same browser profile may be able to open saved records.
Backups and deletion
Export creates a JSON file on your device. Import reads a file you choose in your browser; it does not upload that file to the site. You control where exported files are kept and whom you share them with. A backup may contain the nickname, measurement dates, and heights you entered.
Use the tracker’s clear control to remove its current record and locally saved copy. Clearing the tracker does not delete JSON files you previously exported.
Google sign-in and cookies
We use Google to verify your identity. We store your Google account identifier, email address, display name, and profile picture URL. We do not receive your Google password. A session cookie keeps you signed in, and a separate first-party visitor cookie remembers your two guest predictions. The visitor cookie can last up to one year; signing out does not reset the guest allowance.
Interaction records
We record page views and actions such as prediction requests, sign-in prompts, unit changes, guide visits, and growth-journal actions to understand usage and maintain the service. These records may include the page path, selected unit or formula sex, record count, success or failure category, and time. They are linked to your visitor identifier and, while signed in, your account. Interaction records do not contain entered heights, nicknames, measurement dates, backup contents, passwords, or Google authorization codes. Prediction inputs are stored separately as described above.
Optional website analytics
If you choose “Allow analytics”, we use Google Analytics 4 to understand page visits, visitor numbers, and traffic sources. Analytics cookies help distinguish browsers and visits; technical information such as browser type and approximate location may also be processed by Google. Visitor counts are estimates and do not include everyone who declines analytics or blocks tracking.
Google Analytics is not loaded before you opt in. We do not send prediction inputs, growth-journal records, nicknames, email addresses, account identifiers, or Google sign-in codes to Analytics. We send public page paths, the referring website, and limited campaign labels. Automatic form and site-search tracking, Google signals, and advertising personalization are disabled.
You can change your choice using “Analytics settings” in the footer. Declining stops future Analytics collection in this browser and removes its Analytics cookies; it does not erase data already collected by Google. Your choice is remembered in this browser, where storage is available. Read Google’s Privacy Policy and how Google uses information from partner sites.
Website requests and removal
Normal hosting and security logs may contain technical information such as your IP address, browser details, and requested resource. Signing out or clearing browser storage does not erase predictions, account information, or interaction records already stored on the server. The tracker’s delete controls remove only its local records; they do not delete your server account or exported files. This version does not yet offer account or server-record deletion in the website.
Links to external sources take you to websites with their own privacy practices.