Pheromone

Pheromones were chemicals produced by organic lifeforms. They were predominantly related to sex and attraction. In the 21st century a gaseous entity possessed a human woman; Carys Fletcher forcing her body to develop a series of pheromones that were irresistible to other humans. (TV: Day One)

By the 51st century humans had evolved to produce more highly evolved pheromones, which made them more sexually attractive than their ancestors. (TV: Fragments)

By the time of the 309th Intergalactic Song Contest, Angvians' pheromones were so strong that they could even manipulate a Time Lord's sensibilities. (AUDIO: Bang-Bang-A-Boom!)

On the planet Jora, a living sentient language, the Syntax, was created out of scientists' attempts to create a pheromone language. (PROSE: Syntax)