Purpose of review <p>This review examines recent advances in animal models of same-sex preference, focusing on: (1) the biological factors underlying its development, (2) the experimental paradigms used to measure it, and (3) its neurobiology.</p> Recent findings <p>Recent research has identified several developmental factors contributing to the establishment of same-sex preference, including prenatal stress, aromatase inhibition, maternal immune responses, and order of birth effects. Specific brain circuits controlling sex preference are beginning to be established. Despite these significant advances, methodological limitations remain a major challenge, particularly in how sexual preference is assessed.</p> Summary <p>Sexual preference is defined as the choice of a sexual partner of a specific sex. Animal models are useful for investigating the biological bases of sexual preference. These animal models may reproduce key developmental processes that organize brain circuits controlling partner selection. However, accurately and quantitatively assessing sexual preference remains a challenge. Future progress requires paradigms that capture the multidimensional, context-dependent, and qualitative dimensions of partner preference, thus providing a more comprehensive and biologically grounded understanding of sexual diversity.</p>