> Pretty sure that the percentage of the population that's femaie is at about 50%
Depends what age range you are looking at. The number of males born is higher - about 51.5% of the population. The number of females living is about 51%. More men are born but more men die prematurely.
> Now compare that to the percentage of disabled people. Notice the difference? Good. Now, feel free to extrapolate how many speakers,
Why are we interested in the number of females in the general population? Speakers participate in a conference because they have something worthwile to share about the subject. A very small percentage of men have an interest and expertise in computer programming, an even smaller percentage of women have this experience and expertise. Are you arguing that there are lots of women in the general population, so the organisers should drag them off the street and force them to present a talk about whatever subject interests them?