I would still take issue with the usage of spectrum. A spectrum is a scale with escalating/deescalating and predictable variation. As you go "up" and "down" the spectrum, I don't think you can say how you're supposed to interpret that.
In my opinion, we should be supporting or phasing out concepts depending on its usefulness as a predictive instrument. I don't think the "spectrum" lens offers any power over "two major sexes with many small discrete bins". But the spectrum view does seem forced, as if the intended effect is a more inclusive "we".
Better would be to say that there are two major sexes, as well as some rather rare cases (MOST inclusive definition ~1%). They each belong in their discrete bins as domain-specific studies.
I also think you are letting your concern for humanity cloud your constructs. You seem to be very concerned about exclusion from normal. 70 million sounds like a big number if you were living in Europe at the time of the Bubonic plague. But this is the same problem with large numbers when we hear about state budgets. We hear titanic numbers, but it's hard to grasp how big or small it really is. How big is $100 billion to the state? Medium? A lot? A little? What if I said, hypothetically, that it was marginally less than 1% of the state budget?
Are you going to say to me, "Well, think about how even Bill Gates doesn't have $100 billion. Think about how much that would mean to you." ? If I brought it down to an intimate level, I would never be able to talk about huge numbers because it hits my intuition too hard.