Kids are expensive and the equivalent of taking a second full time job. Let’s also not forget the issue of “marriageable” partners of either sex within prime birthing age. Also, most of the world is seeing plummeting birth rates - Mexico is about to drop below replacement level is one example closer to home.
Well my mom raised four of us on her own after dad died at 36 yrs. We were poor but never knew that. Mom was an exceptional woman and she worked full time.