He found that women preferred the smell of a T-shirt worn by a man who was the most genetically different from her. This genetic difference means that it is likely that the man's immune system possesses something hers does not. By choosing him as the father of her children, she increases the chance that her children will be healthy.
Is It All Just Chemicals?
According to other researchers, love may be caused by chemicals in the body. Donatella Marazziti, a professor at the University of Pisa in Italy, has studied the biochemistrys of lovesickness.9 Having been in love twice herself and felt its overwhelming power, Marazziti became interested in exploring the similarities between love and obsessive-compulsive disorder(OCD).