The question often arises:  ‘do strong women having deeper voices?’
I’ve found over the 20 years or so that I’ve been coaching women that this is too much of a generalization.   Famously, Mrs Thatcher had voice coaching to lower the pitch of her voice to drive home her determination and strength during question time.   Listening back, you could say that she does at times sound like a bully.  Not a label that anyone would wish upon themselves in these times.
What happens when we are under pressure – particularly a lot of pressure, which can happen when we are speaking at important meetings to a large group or in a boardroom, is that the adrenaline kicks in and we go into flight or fight mode, the breath becomes higher in the chest and our voices – particularly female voices – rise.  This can result in a sound which is not going to influence people but rather disturb them.
Once we know that this can happen, the incentive is there to understand that when this is happening to us, there is a way to steady our voice.  We need to release the stomach, allow the lower ribcage to fill with breath and allow the breath to flow back into the voice, from a released stomach.  This will steady the voice.   You need to practice this, so that your way of speaking all the time, is free. 
Some women in high positions in business, have had to develop strategies to be heard.  Especially if what they have to say goes against a male dominated boardroom.  The pressure is far greater for a woman, until she realizes that if she believes, has the experience and has thoroughly researched what she has to offer, she has no less right than a man to say it.  If she is mistaken in any way, then she is equal to her male colleagues, not below them.  In a rowdy meeting, the way to get attention is not to join in, but be ready with a clear opening phrase, ready, so that when you gain attention you can immediately speak.   Remain immobile, sitting back, seemingly impassive, wait for your moment, be patient, it will come and when it does, lift your upper body forward, raise your head, move your arm slightly, you will attract attention and then immediately speak with confidence, in a clear, level voice. You may have to repeat your first phrase while one or two people stop speaking over each other and start listening to you too.