There is an interaction between the Vampire Family aspiration and the other preexisting Family Aspirations. A child can be either your "Child" OR your "Offspring". Not both, ever, for the purposes of these aspirations. I will use the word "progeny" for a Sim descendant so this description is clear. I suspect progeny could be by Woohoo means or adopted, but this testing was done with old-fashioned progeny creation methods.
1. If the progeny is not a vampire it is your "Child".
2. If the progeny is born a vampire it is your "Child", and does not count as "Offspring", even after it ages up to Teen and becomes a vampire. *
3. If you convert a non-vampire progeny to a vampire after they age to teen or older, it changes from "Child" to "Offspring"*
4. If you cure a vampire progeny that is a "Child", it stays a "Child".
5. If you cure a vampire progeny, then bite them they change from "Child" to "Offspring" (you got to case 4 to get to 3 on an alternate path) **
6. If you cure a progeny, that may or may not have been born a vampire, but which you have bitten and is now an "Offspring" they *remain* an "Offspring".*, ***
* The relevant counts in each aspiration will change. So should you bite a progeny which is a child, you get +1 on create vampire offspring and the count for say "Be Friends with 3 of your children" the count goes down by one. Vampire training given to a progeny which is in the state "Child" even if they are your vampire-born progeny does not increment the "Train 3 Offspring".
** That means if you have progeny that was born a vampire, and you want them as part of your Vampire Family Aspiration count, you need to, counter-intuitively, wait for them to age up to a teen and become a vampire, so you can cure them and turn them back into a vampire.
*** If you have a child, which you have bitten, and you cure them, and you want them to count as a "Child" for purposes of the older Family Aspirations, you are out of luck, as they remain "Offspring" unless you go into cas.fulleditmode and manually set relationships.
I would assume if another vampire converts your progeny, that also decrements the "Child" count on these aspirations, since a Sim can be either a "Child" or an "Offspring" but not both I think. So this is something to be aware of if finishing multiple aspirations, or if doing extended family or family rotational play.
