Tamara Brown, 33, is a behavioural geneticist, Her company, GenePartner, offers a service for dating agencies assessing biological compatibility on the basis of DNA, the base it is one of the main factors in the immune system call HLA, the human leukocyte antigen, the theory is the more HLAs you have, the more different pathogens it can bind and instructs the immune system accordingly, so choosing a partner with different HLAs produces a child with a much broader immunity, and that's the final reason (in an animal perspective) of all the relationship, have childs better than the parents, stronger and with more posilibities to be a success, so you have to give them a sample of your saliva and they do the magic.. and surprise! you have your potential lover on the computer, of cuorse, this have nothing to do with love...i mean the real love, or to get on well with someone, this is just seeing in a sexual way, but the scientist says that this is so important to humans that this should be enough, something similar happends when you smell somebody... and you love that smell, it's because of the feromones, it's funny how the "animal instinct" affect us, you can't fight against nature, and this is a good prove of it.

http://www.guardian.co.uk/technology/2010/jul/11/my-bright-idea-tamara-brown