Xykademiqz recently put up an excellent post on the spacing of her kids' ages and her career trajectory, growing out of a question after a post about enjoying her kids. This is an issue that comes up again and again--family, life decisions, and academia. I am linking back to her, and posting this, because I think this is such an important issue. When I was a student, I was convinced that having a family was incompatible with the TT, especially for a woman. This is one of the reasons I didn't even consider an academic position when I finished my PhD. Part of the reason I felt so strongly about this was that up until that point, I had NEVER had a female professor for any of my STEM courses. My undergrad department had one female faculty member (not in my area), untenured with no family. My graduate department had one female faculty member (not in my area), who got tenure while I was a student and then immediately got pregnant, leading to snickering all around by the (mostly) male students and some of the faculty members in the department. There were no counter examples to help me make an informed decision about family and academia--all was rumor and guesswork.
Fast forward to now, and I have both tenure and a family. I had both of my kids pre-tenure. I am a living example that it is possible to get tenure AND have young kids at the same time. In fact, I had one child inside academic (at ProdigalU) and one child outside of academia (at National Lab). From this perspective, I can say that it is much, much easier to have young kids at ProdigalU even pre-tenure than it was at National Lab. Academia is just so much more flexible than most other jobs, and with balancing anything, flexibility is key.
At National Lab, I was required to be at work for set hours. If I needed to be somewhere during those hours, I had to take time off. Since I also got only 12 weeks unpaid maternity leave (the standard FMLA is what Feds get), I burned ALL of my sick leave and vacation time after giving birth, leaving me with practically no wiggle room when LittleProdigal got sick. From observing my colleagues, even after a few years, it is really hard to build up enough vacation time to both have reasonable vacations and be available for kids school and other activities that take place during the workday.
In contrast, as an academic, your schedule is your own. It is long hours, but you set them. Other than scheduled classes and meetings, I can leave work whenever I want to or need to without worry. I don't really ever worry about missing an activity with my kids. Unless I am traveling, it is no problem. This is as true for fun things like concerts as it is for emergencies like sick kids or closed daycares.
On top of keeping track of hours, face time was a thing at National Lab. It was really important to look visibly busy all the time and have the appearance of working in your office or lab for at least 8 or 9 hours a day every day. Asking for time off during the day was frowned upon--better to just take a whole day off then look not serious about your work. Some of my friends in non-academic jobs worry about being mommy- or daddy- tracked, and are reluctant to ask to go to a soccer game or school concert.
There isn't really face time in academia in the same way. As far as I know, no one cares whether I am in my office, or even worries about where I might be when I am not there. I certainly don't keep track of the people in my hallway. There is still a culture of looking busy/complaining about how busy we all are, but there is little or no checking up. Everyone teaches and travels at all different times anyway, so you'd need quite a lot of free time to really track this stuff anyway.
It wasn't super easy to have 2 preschool aged kids while working towards tenure. I worked at home many nights, but at the same time, I was able to reserve the time from 5 pm until 8 pm for family almost every night. I can't imagine that any demanding career is easy to balance with the needs of kids (who can't really wait for many things). In fact, I'd say medicine is way worse (at least until training is done, which can be 7 or more years post-med school), and oddly, medicine is considered a somewhat family friendly career (I certainly was told that a lot when I was a student).
There's never really a good time to have kids, so you may as well have them when you are ready and let the chips fall where they may--you can figure it out in the middle of things without preplanning every second! Not everyone can balance career and family in a way that makes them happy, but don't let people tell you that you can't have kids on the TT, or that serious academics can't have more than one, or that academia is uniquely incompatible with family life, because it just isn't true.