Siri and Cortana Sound Like Ladies Because of Sexism:
It would be easy to credit—or fault—male designers, perhaps influenced by science fiction characters (in Her, for example, or Ex Machina) or, worse, defaulting to the stereotype of a compliant sidekick. But the biggest reason for the female slant rests in social science and its impact on business. By and large, people tend to respond more positively to women’s voices. And the brand managers and product designers tasked with developing voices for their companies are trying to reach the largest number of customers.
Source: Wired