https://thenextweb.com/tech/2019/09/20/google-thinks-it-wasnt-sexist-to-give-its-voice-assistant-a-female-voice/

Last year, a study by the United Nations Education, Scientific and Cultural Organization (UNESCO) argued that voice assistants like Google’s perpetuate “harmful gender bias” and suggests women should be there to assist rather than be assisted. But it turns out Google always wanted to use a male voice, but they didn’t because female voices are apparently easier to work with. 

Talking to Business Insider, Google’s product manager, Brant Ward, said: “At the time, the guidance was the technology performed better for a female voice. The TTS [text-to-speech] systems in the early days kind of echoed [early systems] and just became more tuned to female voices.”According to Ward, higher pitch in female voices were more intelligible in early TTS systems because they had a more limited frequency response and English voices that didn’t come from a human were easier to understand if they took on female characteristics.