prior to joining up i was in Germany as a dependent and i got a job working at the office dealing with married quarters and family welfare. These offices were often run by ex-officers, and were always (as is correct) referred to as Rank (usually at least Major) plus surname.
Anyway i answered bosses phone to have this Major X shouting at me that my boss, Major Y, hadn't answered his phone, hadn't replied to some memos and where the hell was he blah blah. So i took Major X's name and number and left note for boss.
Next morning i got in and my boss said "Major X was really angry" and when i said "gosh yes, he gave me a real roasting" my boss laughed and said "yes lots of people make that mistake. Major X is a woman". And when i finally met her, she was one of those Tweed-Suited women in sensible shoes, and was perfectly womanly in everything apart from her voice. She apologised to me and told me that she used her voice to her advantage on the phone "never let anyone know you are a woman until the last minute, they take you more seriously that way". And i have used that ever since.