I would agree it's more S vs. N than T vs. F re: kids. I'm F and happily childfree, as are several of my N friends, even though we are all married. Most of the childfree couples I know, actually, are Ns. My childfree friends include 1 ENFJ, 2 INFJs, 1 ENFP, and 4 INFPs. Several are now beyond childbearing age.