The scientific community, specifically the community that conducts science on this topic, currently has a distinction on the terms sex and gender. I’d posit the possible consensus position that the term sex refers to physical anatomy whereas gender refers to one’s gender role in interaction with others.

For details on that distinction and attempts at consensus-building for the terminology, see https://journals.physiology.org/doi/full/10.1152/japplphysio...

In software development terms, this topic has no ubiquitous language.

In relation to your comment, their belief is not based in a shared reality.