Back when I was an undergrad at Marist College, a professor in an introductory psych course mentioned the degree to which sexual attraction in most animals is a matter of scent.
Then he paused dramatically and asked: Is it a matter of scent for humans as a well? He answered himself after another pause, "Of course! That's why perfumes and colognes are such big business worldwide, after all."
I've wondered about that from time to time. That is, I've wondered about the size of that industry, but I've never until quite recently wondered with sufficient intensity to do a google search.
Here is some information: http://www.strategyr.com/MarketResearch/Fragrances_and_Perfumes_Market_Trends.asp
According to these market researchers, the global market is projected to reach $40.6 billion by 2020.
For a mere $4,950 I could buy a complete report on this market covering 354 companies in 492 pages, with 138 market data tables.
Cool. I have $5,000 lying around and until now I've had no idea what to do with it....