Sheperd reviews recent research on the mammal and human olfactory system and concludes:

"Together, these findings revolutionize our understanding of the role of smell in controlling the neuroendocrine brain. The traditional distinction that common odours are perceived through the olfactory pathway and pheromones by the vomeronasal pathway is dead. Each pathway must be assessed for a putative pheromone on its own evidence. Humans lack a functional vomeronasal system, but brain scans show that sex pheromones activate wide regions of the human brain, including the cognitive areas15, implying that, as in the rodent, the pheromone-activated endocrine system is much more extensive than previously realized. We have much more to learn about how intimately neuroendocrine functions, controlled by pheromones acting through our noses, interact with other operations within the brain to control human behaviour and cognition. "


(The entire short paper is available online from UNH library.)