Abstract
This paper will discuss the current understanding of biological sex and gender, its limited recording and the subsequent implications on missing persons investigations. The current understanding of biological sex and gender on a binary is inaccurate and can be seen to be insufficient when recording biological sex and gender information about missing and unknown individuals. This understanding ignores intersex, trans and gender diverse individuals and consigns them to either fit the 'normal' binary definitions or else places them along a binary-based spectrum or in a 'indeterminate' category. This is unacceptable, unethical and harmful. Instead, biological sex and gender should not be seen as binary but diverse. The idea of sexual dimorphism should be replaced with an understanding of sexual polymorphism, and biological sex and gender should no longer be defined on a male-female binary, spectrum or scale, but explored on a multifactorial polygon and recorded as such. Cognitive and contextual biases have restricted gender and sexual based inclusion in the long-term recording as the binary has long been considered the 'normal'. This has become a structural way to continue the violence against LGBTQIA2+ individuals, in addition to cis individuals, because everyone is affected by the imposed binary. This paper will highlight the issues associated with this 'normal', expose the limitations of a biological sex and gender binary in the recording forms (from a global sample of 170 forms), and suggest changes to further progress the understanding of polymorphism to improve inclusive recording in missing persons investigations.