One of the problems with equality is that people aren't replaceable units.
You can ask different actors if they'd be interested in playing, say, Jesus in the manger, you'll get a range of valid reactions, and if you ask the wrong person you'll definitely get offense:
- "You saying I'm short?"
- "I'm a buddhist!"
If we're in an important meeting^, and I'm the only member not currently performing a task, then it falls to me to fill the drink of whoever's presenting, if her throat's getting dry. Whether that's my boss, a teammate, or someone under me. Asking me, as a man, to get them a drink is a zero-offense thing, whatever their gender or rank.
[^edit: this previously said "if we're in a meeting with clients" but that was misunderstood to mean "I think the meeting being discussed involved clients". I have rephrased.]
If I'm the one taking notes, and there's another person doing less who is able to do the task, it'd seem a little bit weird. If I'm the one presenting, then I'll assume there's a reason they want me to stop presenting and step aside for a moment, and will be very sensitive to any hints at what the meta-reason for that might be (is my fly undone? Did I say something wrong?)... but still, in no case would I take offense. It would be ridiculous to be offended. Because I'm a man.
If a male asks a female subordinate, that's potentially inappropriate.
[Edit: To clarify, I mean that this is true even if there's no dominance play or sexism involved. It's potentially inappropriate simply because of the configuration of people involved. I am not precluding the possibility that inappropriate behavior can happen with other configurations; I'm just stating that this configuration is particularly fraught with possible misinterpretation.]
It's certainly possible that this was an attempt to show off and make himself "look good" by having obedient underlings, that backfired. In which case, yay and mwahaha. I wasn't there, I can't judge.
But normally, you bring along a subordinate to a meeting to back you up, because you're only one person and can't do all the things. Backing you up includes helping out with questions if they are experienced in the area, and having input into the meeting discussion. But it also includes helping you carry the presentation materials from the car, and so on. "Menial" tasks. It doesn't matter if that person's job description includes those specific things: their task for that meeting is to ease your job of presenting the material and making your case to the other people in the meeting.
From your description of the meeting, it was basically him talking to the field staff.
It would not have been at all appropriate for him to stop the meeting and turn his back to do it himself. That would have been an insult to the field staff.
It would have been even more inappropriate and insulting if he had asked any of the field staff to do it.
As the person assisting him in the meeting, that left you as the only one he could ask. The fact that you were a woman wasn't what it was about, until you made it about that.
If your boss can't rely on you having his back in meetings, then next time he'll ask some guy to take the role instead, because you've scared him off from expecting women to assist him in meetings.
If asking you to perform menial tasks became a pattern of behavior then it's not OK and needs a discussion with him in private, and then escalating to HR in private if that didn't help. But other answers have covered this situation in detail.
From your description, it seems like that's not the situation here. Instead, you let your team down by publicly taking offense where none was offered.
You'll now have a hard time repairing the damage that shows you as "not a team player/quick to take offense" and the loss of trust from your manager.
It's very important indeed that you take the time to discuss it with him calmly, to manage expectations for the future and smooth ruffled feathers on both sides. He was hurt and is human, so that means this will be difficult if you don't lead with an apology yourself. Then honesty and plainspoken openness without hostility will go a long way to getting the apology in return.
You can come out of this smelling better than before you started, because people respect and trust those they fall out with and then patch up better; they feel that they can be honest and disagree with that person without damaging the long-term rapport.