Sexual reproduction in humans is not something that involves “a spectrum”.
For two humans to create their own biological offspring, one of them must be of the reproductive sex class which produces eggs and one of them must be of the reproductive sex class which produces sperm; and they must be sufficiently fertile to produce a viable egg and a viable sperm. In other words a fertile female and a fertile male is required. And they need a human female to carry their foetus in her womb for a sufficient number of weeks before birth. Those “baby farms” in impoverished countries aren’t full of males being forcibly impregnated and held captive until they give birth.
When Stonewall and others start talking about “sex being a spectrum”, they are not talking about reproductive biology (and the two biological sex classes) which enable human infants to be produced.
Sometimes they seem to be talking about disorders of sexual development where a male human’s or a female human’s reproductive system doesn’t develop in the way it should. Sometimes they seem to be talking about “gender expression”.
If Stonewall or others genuinely believe their claims that “there are more than two sexes” then they need to explain how these other sexes go about producing offspring. If they can’t, then they are not talking about the existence of additional reproductive sex classes in humans; the so called “spectrum” they are talking about is something else. And if they talk about eggs and sperm, then they are in fact talking about the two reproductive sex classes that we all know about: the female sex and the male sex.
(Sorry to go on, and I know that you know all this, obviously) but Stonewall and co aren’t going to suddenly discover / provide evidence that there are humans on the planet whose creation did not involve sperm-meets-egg-and-foetus-spends-Xweeks-in-woman’s-womb-before-birth.
They know that. They are being disingenuous. They just want to force everyone, and particularly women, to shut up about reality and spend money on their training courses and tick box exercises; and to kowtow to their Male Access To Female Spaces / Eradication of Women’s Language campaigning.