- There are two and only two genders.
- Okay, then there are two and only two biological genders.
- Gender is determined solely by biology.
- Okay, it’s mostly determined by biology, right?
- Please tell me it’s determined by DNA.
- Gender can be reliably determined through visual means. After all, no man would ever wear a burka.
- Once gender is set, it never changes.
- Even if the gender can change, it will only change from the one value to the other value.
- Only one gender can be “active” at the same time.
- We’re tracking gender now, so we’ve always tracked it.
- I only need to be concerned with human gender.
Source: http://www.cscyphers.com/blog/2012/06/28/falsehoods-programmers-believe-about-gender/
Well this is old af, but I'm gonna put a data science perspective in. Gender is a concept with multiple senses, and you need to be clear which one you are asking users for when collecting that information, as well as clear what the end use case is. You can do that because you're trying to avoid the nonbinary death commandos of Tumblr, or you can do it because you are trying to build a more precise model.