I think it’s self-sustaining, in that the needs of people without kids and the needs of people with kids are super duper different. If all your friends don’t ha

I think it’s self-sustaining, in that the needs of people without kids and the needs of people with kids are super duper different. If all your friends don’t have kids and you do, you feel ostracized because they’re not going to rearrange their life over your kids, and you’re constrained by your kids’ schedules (particularly sleep), so you just don’t see them that much anymore. Conversely, if all your friends have kids and you don’t, most of their socializing will probably feel really alien to you (unless you’re a teacher or something and work with kids), so you’ll feel disconnected from them. Anecdotally, in my friend group, once the first two people had kids and started hanging out with each other, it was like the flood gates opened.