Falling in love is a human dynamic, and apparently also of certain animals, characterized by a strong and active emotional participation of a subject toward an other subject Few pre-eminent and internationally renowned sociologists/psychologists have developed a comprehensive treaty of the subject, and the most renowned have been developed by Denis de Rougemont and Francesco Alberoni. In his socio-psychological theory Francesco Alberoni states that falling in love is a process of the same nature as religious or political conversion. People fall in love when they are ready to change, or to start a new life. According to Alberoni, falling in love is a rapid process of destructuration-reorganization called the nascent state. In the nascent state, the individual becomes capable of merging with another person and creating a new collectivity with a very high degree of solidarity. Hence the definition: falling in love is the nascent state of a collective movement formed of two people only. In order to understand if someone is truly in love, the individual must be put to truth tests and, in order to find out if he or she is loved in return, the beloved is also put to reciprocal tests. The incandescent process of the nascent state through these tests gives way to certainty and produces a stable love relationship. According to Alberoni, the phenomenology of falling in love is the same for young people and adults, for men and women and for homosexuals and heterosexuals: this is because the structure of the nascent state is always the same. Unlike the theories consolidated by psychoanalysis, the sociologist does not consider falling in love as a regression, but instead sees it as launching oneself towards the future and change, and thus as fundamental to the formation of a couple in love.