Sex determination, the process of developing testes or ovaries, is a conserved process amongst most mammals. This is largely controlled by the Y chromosome gene, Sry. This triggers male specific gene expression by activating Sox9, and concurrently blocking expression of female specific genes. Low levels of conservation outside the DNA binding domain HMG-Box, make analysis of human Sry in mouse or other species difficult. The N and C terminal domains of hSry have no known function, but mutations in these regions have been identified in patients with disorders of sex development (DSD), suggesting important roles for protein stability or cofactor recruitment. To understand the structure/function relationship of Sry in humans, we have generated a single copy transgenic mouse model expressing human Sry (hSry). This produces chromosomally female, but phenotypically male mice. By generating mutations within each of the domains using CRISPR delivered by electroporation we can assess the functionality of various patient mutations as well as domain deletions on Sry action during sex determination. Using this method we have shown that the C terminal domain is critical for function, and in vivo evidence suggests the N terminal domain is also required. This mouse will be a useful tool in which to model human sex determination, study SRY mutations of DSD patients, and will help to further our understanding of the structure/function relationship of human SRY.