Superior Olfactory Perception in Males

• Bourgeonal is an aromatic compound with a scent similar to the lily of the valley flower, which is used in the production of perfume. A study published in the June 2010 issue of "Chemical Senses" addressed the differences in the olfactory sensitivity to this compound between males and females. The researchers tested 250 male and female subjects and found that males detected the scent at 13 parts per billion (ppb), whereas females detected the scent at concentrations of 26 ppb. The authors stated that this is the first study to show a superior olfactory perception in males.
  
  

Gender and Olfatory Receptors

• The June 2007 issue of "Nature" included a study investigating the genetic variation of olfactory receptors in males and females. The researchers investigated the role of an odorous male hormone, androsterone, derived from testosterone, on an olfactory receptor responsible for the perception of various odors. The study found that genetic variants of the OR7D4 olfactory receptor had different responses to a panel of 64 other odors and concluded that the human odor receptor was genetically programmed to find scents either pleasant or unpleasant.
  
  

Olfactory Receptors are Sexually Determined

• Kisspeptin is a mammalian protein that promotes a cascade of events in puberty, such as the release of gonadal releasing hormone, a precursor to sex hormones, which directs sexual behavior in adults. A study published in the August 2007 issue of "The Journal of Neuroscience" investigated the effects of kisspeptin on olfactory receptors responsible for sexual preference. The researchers used mice for their experiment. The study found that neutered male mice treated with testosterone regained a preference for females, but the same was not true of female mice. The researchers further found an increased number of kisspeptin receptors in males in comparison to females.
  
  

Sense of Smell and Parkinson's Disease

• Parkinson's disease is a neurological disorder characterized by shaking and impaired movement. The disease is thought to occur due to reduced levels of dopamine, a neurotransmitter, and occurs more frequently in men. An article in the June 2008 issue of "Movement Disorders" examined the relationship between dopamine receptors in the olfactory bulb, a sensory network in the brain, and gender. The researchers compared the number of cells that respond to dopamine in males to females with Parkinson's disease. The study found that the number of cells with dopamine receptors of either gender with Parkinson's disease was equivalent to the number found in healthy males of the same age group, indicating an increase in receptors in females with the disease.