I’m a parent of three kids (all under 7), and I’m also the Cofounder of a startup that is doing quite well so far (though we are still early).
I would say that it all depends on funding. I have bootstrapped before, and I could never do that now. Perhaps more accurately, I would not want to do that now.
Having raised funds for this start up, my salary is a lot lower than it was working in enterprise, but it’s enough to support me and my family.
I have two Cofounders to share the load. One is also a parent, one isn’t. They pull a lot of weight, but none of us have to work ourselves to death. Having a good founding team is crucial.
My wife is at home full-time - Chief of Domestic Operations - and that’s what makes it work. Because she enjoys that role and I can feed us all, things work out.
With that support structure (funds, founding team, supportive spouse), it’s very doable. Still hard work, but the very enjoyable good kind of hard work.