Y Combinator is probably one of the most prominent tech accelerator and seed funders in the country. The competitive program helps start-ups get a leg up in the industry by providing guidance, funding and access to a huge network of industry insiders. The accelerator helped famous names like reddit, DropBox and AirBnB get off the ground.

But it has some gender issues: Barely a quarter of the start-ups it funds include  even one female founder. This isn't a problem unique to Y Combinator — throughout the tech industry, women are underrepresented due to a variety of factors, especially in more technical roles. And at least Y Combinator knows this is a problem and is trying to fix it — the accelerator even hosted its first "Female Founders Conference" last weekend.

In a blog post wrapping up the conference, Y Combinator posted this chart illustrating the progress they've made in drawing women into their bootcamp-like process during the past nine years.

The chart shows the percentage of start-ups with at least one female co-founder in their program. At first glance, it might suggest that they are pretty close to gender parity — until you notice that the Y axis scale only goes up to 30 percent.

Twitter user Shanley noticed that issue — and superimposed Bureau of Labor statistics data on women in computer and mathematical occupations that suggests that Y Combinator's gains in the area still leave women underrepresented in terms of founders supported by the accelerator even based on their proportion of the industry.

Another Twitter user, Kevin Marks, agreed there was a clearer way to display the gender (im)balance at Y Combinator. So he made a chart comparing the percentage of start-ups with at least one female founder to those with at least one male founder. It's a very different chart.

From this view, it's actually clear that Y Combinator funds three times as many start-ups featuring exclusively male founders as it does start-ups with at least one female founder. In his research for the chart, Marks could only find two start-ups with exclusively female founders.

Y Combinator founder Paul Graham got a round of bad press last winter for comments about why there are not more women in the tech industry, although he has argued his comments were taken out of context.