Each child born singly counts as 1 child.
The first set of twins (if any) only counts as 1 child.
The second set of twins counts as 2 children.

The third set of twins counts as 3 children.
Triplets (or more) count as twice as many children as are in that set, minus 2… (i.e., triplets = 4, quadruplets = 6, quints = 8, etc.).

I have no strong preference for boys or girls… but a mix of both would be nice.