This is definitely part of it. If I get the impression that at least it's something the company cares about and is working on, that helps.

But also, as you mention, many companies have disappointing gender ratios, so it's not like I'd pass on a company purely because of that. It's more like another data point to consider. And conversely, if a company does have a higher portion of female engineers, that will weigh strongly in its favor.