Five weeks into development, a human embryo has the potential to form both male and female anatomy.
From reading the article, it seems as if this may be technically true, in the sense that an embryo with XY chromosomes may be somehow blocked from these being expressed or vice versa. But this is an anomaly. It seems that we can say that an embryo with XY chromosomes will become typically male except in extremely rare cases where things essentially go wrong.
It seems to me a bit disingenuous to describe this as a spectrum. Sure, there are ways in which mutations and differences occur, and because it's a complicated process, these can occur in many different ways. But at least 99% of people (and far more by most definitions) are either on one end or the other. For the remaining inter-sex people, I guess its a spectrum.