Stuttering: "Talk with continued involuntary repetition of sounds, esp. initial consonants"

The definition of stuttering involves having problems with physical speech. The definition of woman doesn't involve having problems with physical speech.

Stutterers are underrepresented in most conferences; even if you could get them up on stage, it would be a difficult presentation to listen give eloquently (and probably hard to listen to). Women are underrepresented at conferences, but it's not because they would have a problem presenting. Some people might have a problem listening to it, but that'd be largely because of their own issues.

Comparing stutterering - a physical (or perhaps mental) impediment - to females is insulting.

You've missed my point entirely. To restate it more bluntly, being a presenting female at a conference can cause a mental impediment. Would I prefer to listen to a female speaker than a stutterer? Not if she were so paralysed by self-doubt that she gave a halting, unconfident, impossible to listen to talk.

I didn't miss it at all. It's just not a good point. What about male presenters who get paralysed or nervous or have self-doubt in front of crowds?

I've seen few female presenters bomb, and the ones that did - there were much easier explanations - no or little experience public speaker, didn't understand the topic, etc. The ones I've seen who know the topic and the audience and have spoken before in public are fine - no better than men. I do have occasion to listen to male speakers who stutter, and while I know they're smart people - they know their subject well - they can not present.

In your example, it seems obvious that the speaker's gender isn't the source of the hindrance - instead, shouldn't it be the audience of misogynists that are at fault as the hindrance?

The gender infers the audience whether it in fact exists or not.