Human beings have an innate awareness of potential threats and dangers which enables them to react accordingly. Researchers believe that such behaviors might also be practiced by the body's internal systems, particularly the immune system. The perception of illness, negative emotions and other undesirable characteristics in a person, place or situation might cause one to execute the natural response of immediately avoiding or escaping such people, locations and circumstances. 

The Behavioral Immune System 

Psychology researchers theorize that all people possess a "behavioral immune system," as well as the well-documented biological defense mechanism, or physical immune system which is designed to protect the body from invaders that might cause illness. The concept of the behavioral immune system has been in existence for slightly more than a decade. However, during that time, numerous psychological and social scientists have conducted studies putting this opinion to the test. One of the more recent examples was conducted by a team of researchers representing McGill University in Montreal, Quebec in the nation of Canada. 

Perception Can Determine Attraction Or Repulsion 

These Canadian scientists suggest that the habits and actions some individuals exhibit may be a significant determining factor in whether others will find them physically or romantically pleasing. The examiners theorize that people who display signs of illness such as coughing and sneezing or those who display poor hygiene, for example bad body odor or appearing dirty and unkempt, greatly reduce their chances of finding physical or even romantic attraction. 

The Immune System Influences Love, Say Researchers 

The McGill researchers studied the habits of hundreds of single, heterosexual individuals and subjected them to either in-person meetups, online speed dates or required them to peruse through dating profiles and highlight which individuals they were attracted to. Furthermore, before the "dating process" began, each subject was asked to fill out a questionnaire designed to give the examiners an idea of whether he or she demonstrated significant concern over the prospect of contracting illnesses from others (a medical condition scientifically referred to as germophobia) or not. 

The researchers found that those individuals who displayed cleanliness, exhibited proper hygiene and whom the subjects deemed to be disease-conscious were perceived more favorably than those who did not express such attributes. The study's examiners further confirmed their conclusions by also subjecting one half of the subjects to a viewing of a brief film highlighting disturbing hygienic practices with the other half watching a non-descript video. Following the viewings, each group's dating and mating habits were again examined. Those who viewed the snippet on bothersome hygienic habits exhibited significantly more discriminating tastes in identifying potential romantic partners than the individuals who did not witness the film in question. 

The Human Leukocyte Antigen (HLA) 

Immune System Influences Love Life, Say ScientistsAnother recent study, which was published in Nature Magazine, puts forth the notion that the Human Leukocyte Antigen (HLF), a substance embedded inside a person's immune system that enables individuals to detect foreign cells and particles, might actually play a role in the attraction process. Study conductors examined more than 250 couples and found the greater the difference in each partner's HLA, the more likely they were to not only connect, but also express the desire to have children. Moreover, subjects with vastly different HLA's were also discovered to enjoy specific attracting attributes in their respective partners such as body odor. Researchers who completed this study suggest that such conclusions might indicate that the body is a fairly reliable predictor in terms of identifying a potential romantic partner. 

Overcoming Germophobia and Other Negative Perceptions When Dating 

Though first impressions are hard to ignore and might confirm the worst fears individuals may have about others, these initial thoughts are not always indicative of who another person truly is. Therefore, people with germophobic tendencies might greatly limit themselves in the attraction game if they do not find ways to overcome their fears. Some germophobic individuals might put their minds at ease and widen their pool of potential mates by:

Focusing on One's Own Cleanliness and Hygiene 

Many common viruses such as the ones that often cause the common cold can be avoided or eliminated by practicing hygienically-sound practices like frequently washing your hands with warm water and soap and not touching your face, eyes or nose after making contact with surfaces found inside public venues such as shopping malls or movie theater restrooms. 

Realizing That Obsessing Over Cleanliness Could Indicate More Significant Issues 

While practicing good hygiene and maintaining the desire to protect one's health is a normal and worthwhile endeavor, becoming fixated on this issue to the extent it limits where you visit and who you socialize with may indicate that one has a mental disorder such as obsessive-compulsive disorder (OCD) that might need correcting.