@Me1620 The ChallengeData.package can become corrupted and prevent players from receiving badges they have otherwise earned. By the look of things, file corruption can prevent some badges from even showing in-game, whether they've been earned or not. If the file is corrupted, it has to be regenerated; you'll certainly lose your progress on unearned badges, but it can't be helped.
The Head of the Family badge seems to be a special case. It's not enough for a sim to have 30 grandchildren. I believe the sim has to be female, has to have at least two children contributing grandkids to the tally, and has to be designated "head of the family." For a couple, which sim is the "head" is often unclear, but it may be the older one. When I wasn't getting this badge, I temporarily killed off the husband (and didn't save) just to make sure. Finally, the badge is triggered when the grandmother has another child, which can happen through adoption.
This progression worked for me the first time I tried it, even though the (male) sim in my previous save had more than enough grandkids. So if you just want to trigger a badge you should already have, you could try it out. If it doesn't work, it's probably time for a new ChallengeData.
