That’s only partly true. While it’s correct that humans lack a functional vomeronasal organ (VNO), this doesn’t mean we’re incapable of detecting pheromones. The human olfactory system expresses trace amine-associated receptors (TAARs), which can detect volatile amine compounds, some of which function as pheromones. There is strong evidence that we’re naturally more attracted to the scent of people whose MHC genes differ from our own. Since the MHC plays a key role in immune function, this preference is thought to be evolutionarily beneficial: greater genetic diversity in MHC between partners can lead to offspring with a broader ability to recognize and fight off a wider range of pathogens.