I do have MCCC, although there was one time when I placed a background sim (it was Commander Shepard) and MCCC married him off. He was close to being an elder and they still didn't have kids, so I went into CAS, aged them down, and gave them a toddler so that they won't die out.
There was also another time when my sim's husband had a sister that I didn't want to keep around in the house, so I married her off to Alexander Goth and let them have a kid. When the kid was born, I moved them out and let MCCC do the rest.
Otherwise, I just let MCCC do the work and I intervene if it's someone I find interesting.