As I mentioned in the previous post, by adding the condition that a family with two children has a girl named Florida the odds go from 1:3 to 1:2 that the other child is a girl.
Florida was one of the top 1000 female names between about 1900-1930 according to Mlodinow and the Social Security office. But now let’s say it’s a 1:1,000,000 name for girls. The possibilities for families include (assuming they won’t have two girls named Florida): (b,b), (b,n), (b,F), (n,b),(n,F), (n,n), (F,b), (F,n), where b=boy, n=girl not named Florida, F=girl named Florida.
Since we know the family has a girl named Florida we can throw out (b,b), (b,n), (n,b), and (n,n). That means there are 4 ways to have two children families with a girl named Florida, (b,F), (n,F), (F,b), and (F,n), two ways with boys and two ways without.
For more nuanced analysis of this problem check out:
There once was a girl named Florida (a.k.a Evil problems in probability)
Two-Child Paradox Reborn?