Would they have forgone more income than the cost of fertility procedures had they had kids earlier though? Besides, if you use a surrogate mother and use donated or frozen eggs and sperm, you sidestep the higher probability of birth defects.
> it's nice to be relatively young and healthy when you're chasing toddlers
Why the assumption that you'll be not so healthy in your 40s and 50s? My parents had me in their late 30s and they didn't seem to lack for energy compared to what they and their friends remember of their 20s. Hell, I'll bet even if they had more kids right now they'll still have the same health and energy.
But that doesn't offset the cost. Surrogates are still enormously expensive. And, presently, introduce legal concerns (whose kid is it) depending on the country and state.
> it's nice to be relatively young and healthy when you're chasing toddlers
Why the assumption that you'll be not so healthy in your 40s and 50s? My parents had me in their late 30s and they didn't seem to lack for energy compared to what they and their friends remember of their 20s. Hell, I'll bet even if they had more kids right now they'll still have the same health and energy.