I used the grant youth on a nursing mom, and she carried the baby until she was old and died, LOL. I never knew what happened to the baby, because it did not show up in the grave or with the kids. However, I did go down to one less person in my population, and could not replenish that one person (no more babies were allowed to be made). So, I had a max population at 97. I won't grant youth to a poor nursing mom again. ;-)