Do you even want kids? If not, then what's the point of the question.
Yet again since I know you've gotten this advice multiple times in the threads you've started, I'd encourage you to read the blog. In the MMM context, FIRE is about evaluating your spending priorities and spending wisely to actually make yourself happy. It is not about saving every possible penny. If it was, MMM would not live in a medium COL place or have a child. Or a nice house. Or, or, or.
That said, it's a whiny, complainypants (READ THE BLOG--that's a MMM thing) excuse to say that if you have kids you can never FIRE. If you want to make it work, you will. If you don't, that's fine, too. Certainly, not everyone needs to have kids. I'm married, and my spouse and I don't, even though we were married in our 20s and our childrearing ages are nearly over. I don't regret that one tiny bit and I would do it again exactly the same. But if you want them, you can find ways to make it work, just as thousands of other FIRErs have.
You see to be looking for reasons to dismiss the FIRE lifestyle. (This post, as well as your other threads.) If it's not for you, cool. But all this is based on the blog, which you haven't read. So start there, rather than asking others to do the work of spoon-feeding it to you. Because part of the MMM culture is a DIY, figure it out yourself, don't be lazy and needy kind of mentality.