Yup, that's what happens to me too. To get my point across, I've had to use attention grabbers like "Gentlemen" (when I was the only woman there), or "This is how I think we should proceed", or addressing the person with the loudest voice by name and then taking advantage of the slightest lull in the conversation. I'm pretty sure this is what guys do too. The only difference is they've been socialized to do so at an earlier age than us, so we just have to catch up!(... and this is NOT being "less feminine")
Once I get started with what I have to say, the men have no problem listening and valuing my contribution.
I've had the same problem in my own family when sitting around the table with my three sons. And I know they do not think my contributions to the conversation are less valuable than theirs. It's just a question of defining my space and carving it out, just like men.
As to male vs female privilege in general, women have traditionally deferred to men in some areas and men have traditionally deferred to women in other areas - we each have our stereotypical areas of "expertise" - although the gender gap is narrowing there too. The only areas where the gap will not narrow so much is anything to do with physical size and strength.
To Isha ... you have a thread about this and I just want to say that you already know how to carve your space, so you shouldn't experience any issues with having your voice heard? Having a stronger physical voice does help, but it is not essential.