>>76733543
I don't know if he ever explained it properly but I can say what the real mechanism is.
The Y-chromosome mostly codes for testicular development. When testicular development is poor (or damaged from steroids) then sperm quality will go down.
Y sperm are faster and more powerful but burn out faster.
X sperm are more slow and steady and finish the race more consistently.
Thus, nature made it so that Y sperm are more difficult to manufacture correctly.
This means that better balls are more likely to produce boys, which in turn gives those boys better balls and better sperm.
Worse balls are more likely to produce girls in order to prevent passing down bad testicle genes.
But in the end it's a percentages game and good balls produce girls all the time.
