There are 2 sexes: male and female. Biological sex is not a spectrum.

There are 2 sexes: males and female. Biological sex is not a spectrum. Expand
There are 2 sexes: male and female. Biological sex is not a spectrum.

According to an Endocrine Society Scientific Statement [1],

Sex is dichotomous, with sex determination in the fertilized zygote stemming from unequal expression of sex chromosomal genes.

Sex differences in baseline physiology and associated mechanisms form the foundation for understanding sex differences in diseases pathology, treatments, and outcomes. 

The erroneous claim that biological sex is a spectrum, or non-dichotomous, is often used to justify the ideological assertion that all humans are ‘assigned sex at birth’. In fact, biological sex is encoded in every cell of the body [2].

REFERENCES

[1] Bhargava, A., Arnold, A.P., Bangasser, D.A., Denton, K.M., Gupta, A., Hilliard Krause, L.M., Mayer, E.A., McCarthy, M., Miller, W.L., Raznahan, A. & Verma, R. (2021). Considering Sex as a Biological Variable in Basic and Clinical Studies: An Endocrine Society Scientific Statement. Endocrine Reviews 42 (3): 219-258. [Link]

[2] Shah, K. McCormack, C. & Bradbury, N. (2014). Do you know the sex of your cells?’ American Journal of Physiology – Cell Physiology, C3-C18, 306, 1. [Link]