The same issue comes up every time I mentor technical women:
"I offer an idea at a meeting, no one listens to me and then a man says the same thing and everyone listens."
Often the woman is the only woman on a team and so the only woman in the room. Often they are smart, nerdy and not very assertive. Sometimes, not always, they are very polite too. Their ideas get overlooked and it's very annoying (and career stifling) for them.
My advice when a woman brings this up is always toughen up, get over it and learn how to assert yourself in a male world. Until you are the boss, or you are in a team that is 50% women, you need to learn how to talk like a man. You don't have to be masculine, but you do need to be understood. If you went to France to work on a team of French people, you would learn French. If you work in a world of all men, you need to learn how to talk Man.
There is a book full of insight on how to do this -- Deborah Tannen's brilliant You Just Don't Understand. Professor Tannen points out that the way women talk creates connection while men's language transfers information. (This is especially true of engineers). Women are creating community as they speak; men are establishing status. We are brainwashed by the media -- women create the home, men are on the hunt. So while we make nice, men figure out who's on top (status-wise of course).
Knowing this is power and the start of the solution to the problem of your ideas being ignored. Complaining about it is a waste of time and energy. Take an assertiveness class, practice speaking up and being heard, find a man on your team who will listen to your desire to change and who will help you. But don't expect the group to change; that's an unreasonable expectation until your group has a significant percentage of women in it.
There is one other thing that can also help with the mental toughness necessary to be gender-isolated every day at work and that is to sign up for some challenge that stretches you and raises your confidence and assertiveness at the same time. Train for a half-marathon, sign up for a weekend hackathon, do a triathlon, join Toastmasters -- and then take the same steel that your challenge requires into your meetings, and remember to smile as you make yourself heard.