Riddle

Families stop childbearing after 1st boy. Sex ratio?

Choose an answer

A.More boys
B.More girls
C.2:1 ratio
D.01:01:00
Hint: It's a word with 0 letters, starting with "0".

Answer

01:01:00

Why this is the answer

Every individual birth has a 50/50 chance. No matter the 'stopping rule,' the total expected number of boys and girls in the population will remain equal.

This riddle is filed under Expert Riddles for Adults and rated Hard.