I looked for the part where her being a mom made any difference what so ever. It must be hard to be away from your children most of the week and of cause taxing on her partner, but that's not really unique to YCombinator or startups.
It's not about her being a mom helping or hurting. It's about Her being a mom and going through YC. I think this kind of post can inspire other women with kids to see "maybe I can do it too."