So much debate around whether sex is a binary or a spectrum. The thing is, a binary is a mathematical thing. And there isn’t any need to debate mathematical things. They are easy to prove.

I’m a computer scientist, and if there’s anything we know, it’s binaries.

Let’s start with this. When you have two things, there are four ways to combine them. You can have the first without the second, the second without the first, neither, or both:

1	0
0	1
0	0
1	1

That’s it.

And now: sex. It’s not a coincidence that the word for sex, as in whether you’re a man or a woman, is the same as the word for sex, as in gettin’ it on between the sheets. They both have to do with reproduction.

There are two gametes in human reproduction: the smaller one, called the sperm, and the larger one, called the ovum. If you have those two things, you can make a baby. If you don’t have those two things, you can’t make a baby.

If you have those two things, you can make a baby in a petri dish. Even if there’s no boobs, hips, penises, vaginas, estrogen injections, silicone implants, lingerie, gaffes, tool belts, laser salons, cosmetic surgeons, or anything else anywhere in sight.

If you don’t have those two things, you can’t make a baby. Not in a petri dish. Not anywhere else. Even if you bring all the asymmetrical haircuts and stilettos and ambiguous genitals and pink and blue flags and bathroom bills and clownfish you can muster.

There’s only two things that are needed to make a baby. A sperm, and an ovum.

There are four ways to combine those two things in a human being. The person can produce ovum but no sperm, sperm but no ovum, neither, or both. In reality, the last is exceedingly rare. But the point here is that there isn’t more than one way to do this math. This is a classic binary system. Two things, four combinations. There’s no way to get an endless number of combinations out of two things or even seven combinations out of two things.

Since it takes a sperm and an egg to make a baby, and the question of whether or not folks want babies coming into their lives is an important one to absolutely everyone, it’s useful to have a word for those who make sperm and those who make ovum. Until recently, everyone’s been happy to use the words “male” and “female” for this useful distinction.

But even if you decide these words are harmful, even if you ban them, even if you question and censor every other word that springs up in their place, there will still be two gametes and four ways to combine them. Math is inflexible that way. Reality is stubborn that way.

Intersex? Despite the hype–which tellingly is spread mainly by folks who aren’t intersex–that’s a handful of conditions, and those are disorders of female development or disorders of male development. But it wouldn’t matter if there were a thousand intersex conditions. All intersex individuals produce sperm, ovum, both or neither. All fit into one of the four available combinations. In no cases does a human being produce a third gamete! Or a fourth!

Now if you want to say gender is a spectrum… well, I’ll still say that’s a mistake. But at least it’s not mathematically refutable in five minutes.

A position that requires bolstering with fake data is a weak position.