There are many biometric modalities for identification of persons. Recognition by fingerprints and DNA profiling are better than lip prints, foot prints, iris pattern, voice, gait and handwriting but no single system is perfect and every system has its own limitations therefore these methods are used in combination. In addition to these factors body odour is one such biometric modality which has been less researched as compared to others and it has its own strengths and weaknesses.
There are various theories about production, collection and using of human scent as a source of identification. Usual source of scent comes from the skin so it must be from one of the secretions of the skin. In addition to skin this odour can also emanate from breath and excreta of person. Microbiota present on the skin is also responsible for the smell of the person and mosquitoes are attracted to the person by this smell. As there are different bacteria on different persons causing different scents that is why mosquitoes are attracted in a different way to different persons.