Even a man was using one, even though males don't get any periods, and it claimed his menstrual cycle was due
https://www.bbc.co.uk/news/technology-55146149
Quote
One man said his smartwatch had a menstruation tracker activated by default when he got it, and it kept telling him his period was "due" - despite him never having had one.
Sorry to all the women, but I had a laugh at that bit