|Cover to the 1999 film "Sexual Chemistry", with the subtitle: Chemistry 101 was never like this? (See: Human Chemistry 101).|
Early views on what defines sexual chemistry often fell on the hormone theory of love. Author Tony Hargreaves, for instance, describes “sexual chemistry” as the effect on body chemistry that “bursts into our lives in early teens”. 
In a generalized sense, theorizes often attribute good sexual chemistry to not only to good grooming, appearance, healthy body fitness, a sense of humor, etc., but also significantly to smell. As based on the 1995 sweaty T-shirt study, good sexual chemistry has recently been defined as those sexual parings wherein partners have the most dissimilar immune systems, as can quantified by six markers on the major histocompatibility complex (MHC).  The matching site ScientificMatch.com, created in 2007 by American mechanical engineer Eric Holzle, for instance, claims to be able to create sexual chemistry in matches by having people send in samples of their saliva. 
A recent 2003 study conducted by Satoshi Kanazawa, of the University of Canterbury, for instance, tracked the biographies of 280 great scientists and found that great discoveries resulted from a great sexual drive, correlating to heightened testosterone levels. 
The 1999 film entitled Sexual Chemistry (pictured), written by Helen Haxton, was based on the theme of sexual chemistry.  In TV and film, certain pairs of actors and actresses, such as Bruce Willis and Cybill Shepherd in Moonlighting, are often described as having heightened levels of sexual chemistry. 
1. Fast, Julius and Bernstein, Meredith. (1983). Sexual Chemistry: What it is, How to use it. M. Evans.
2. Hargreaves, Tony. (2006). Chemistry of Sex. LuLu.
3. Henderson, Mark. (2003). “Secret of Genius is Sexual Chemistry”, The Times Online, 10 July.
4. Holzle, Eric. (2008). “ScientificMatch on The Today Show” (interview with Eric Holzle), Feb.
5. Sexual Chemistry (1999), starring: Jeff Xander, Stephanee LaFleur; Director: Mike Sedan.
6. Lester, Benjamin. (2007). “Sexual Chemistry 101”, Cosmo, Issue 15, June.
7. Chemistry (Bruce Willis and Cybill Shepherd) – DavidandMaddie.com