The distant country of Toomalia has a birthrate of 67 boys for every 33 girls. In an effort to restore a 50:50 gender ratio in the country, Toomalian policymakers institute a mandatory new social policy: Couples seeking to have children may continue to do so as long as they bear only girls, but must stop as soon as they bear one boy.
Assuming the Toomalian people i) rigorously adhere to the policy, and ii) do not selectively abort their offspring, what will the net effect on the boy:girl birth ratio be when the new policy is put into effect?
Note that you may assume the gender of each conceived child is independent from the gender(s) of its siblings, but you should not assume that every couple wishes to conceive as many children as possible. Many couples will voluntarily stop having children after having 2 or 3, for example.