When we, some of my peers, talk about "child processes"...
20 years ago the discussion was around the question of "who all is running netrek, and can we have someone who is root kill their process?". This was a quality of life issue, a very real first world problem.
15 years ago it was about zombies. Software usage was such that we started noticing quality. Child processes that became zombies. Seriously, zombies.
10 years ago it was all about tuning Apache such that it had the optimal number of "children" such that you would not go into swap because you miscalculated the amount of memory that would be used. We often had too many children.
5 years ago the debate around child processes vs threads became a real conversation due to the changes in hardware.
I find my peers talking about child processes and sleep time, where child processes are in the 1 week to 12 month range with a average sleep time that is anywhere between 2 and 8 hours.
*) Can you find reversed joke in the above statement?