Human Sex Recognition: A Developmental Voice-Centered Model

Human sex recognition is a universal human ability, yet its biological and developmental basis remains incompletely characterized. Research on pheromonal signaling in animals has been essential for elucidating principles of sex recognition, social development, and multisensory integration across species, and has profoundly informed hypotheses about human behavior. However, in humans, no specific sex pheromone has been identified, and the anatomical and genetic substrates required for pheromonal communication—such as a functional vomeronasal organ and intact vomeronasal receptor gene families—are vestigial or absent. These observations suggest that additional or alternative mechanisms may play a central role in human sex recognition.This manuscript proposes the Human Sex Recognition (HSR) model, a developmental framework in which the human voice functions as the earliest and most reliable biological cue to sex. Drawing on converging observations reported across the scientific literature, the model integrates evidence that infants exhibit early sensitivity to vocal signals; that children form stable auditory–visual associations linking voices with sexed visual features; and that pubertal hypothalamic changes confer motivational and emotional significance on these learned associations. The manuscript is organized in two parts. Part I presents the formulation and developmental foundations of the HSR model. Part II evaluates empirical, biological, and comparative evidence bearing on human sex recognition and examines how the HSR framework complements existing pheromone-based sex recognition (HPSR) accounts.Although no new dataset is introduced, the synthesis of human developmental, perceptual, and neurobiological research indicates that HSR is supported by extensive real-life exposure, large effect sizes, and biologically plausible learning mechanisms. The HSR model incorporates mechanisms well established by pheromonal research while proposing additional developmental processes in domains where pheromonal explanations appear insufficient, thereby generating testable predictions for future experimental and developmental studies.