It sounds like they don't define as either male or female because "there are certain advantages and disadvantages to being a specific sex or gender."
What always interests me in these articles though is the way that they think about the world. So the argument in the article is 'they' (not sure if that's the right usage) can identify as something and therefore change the reality around them. “DEAR INSTAGRAM: THIS ISNT SEXUAL”, defining as a female is not what makes breasts/ nipples sexual, it is the fact that they are used/ enjoyed sexually (as well as other ways of course). That's the reality around them that they're within, you can't change that by 'feeling' a certain way.