Transgender, gender diverse, and intersex (TGDI) individuals face significant health disparities due to individual and systemic experiences of discrimination, impacting their access to healthcare. While clinical genetic testing has become increasingly accessible to the general population, the field of clinical genetics perpetuates a narrative of biological essentialism, which creates barriers for TGDI patients. Biological essentialism upholds that sex is a binary, fixed, and innate characteristic, a misconception that has been historically weaponized against the TGDI community in both individual experiences of discrimination and anti-trans legislation, among other systemic forms of oppression. Rejecting this discriminatory framework requires careful consideration of, and changes to, long-established practices that often go unquestioned, such as quality control metrics in genetic testing, in order to improve TGDI patients' outcomes and access to genetic services. The sex-check, comparing an individuals reported sex against their sex chromosomes, is an example of how laboratory genetics practices reinforce the narrative that sex is determined purely by chromosomal composition. Additionally, the sex-check "outs" TGDI people in clinical settings, creating a discriminatory and unsafe environment for these patients. Alternative quality control procedures and inclusive practices, such as clearer delineation of sex and gender on test requisition forms, are proposed to improve TGDI patient experiences. Genetic counselors and other clinical providers have a responsibility to address historical discrimination and advocate for changes to laboratory practice, so as to create affirming experiences for TGDI patients.