Do we need to go over where babies come from? Because there's only one way that happens, and it requires to different type of people. We have words for that (male/female, man/woman) so, if we want to engage in the second primal instinct, we know who to chat up.
That's it. That's all there is. %.02 percent of the population with ambiguous physical characteristics does not magically create a new way to make more of ourselves. That's what the words mean. Full stop.
If someone wants to grow their hair long, change their name, and take pharmaceuticals to make themselves feel better, then more power to them. But under no uncertain terms is anyone to force the rest of us to lie about it.
Two plus two make four.