Actually boxers keep you fertile because they allow your balls to remain cool. If their temperature gets to high from your body heat they cannot manufacture sperm. Hence the reason your balls are outside your body and not inside.
This is also the reason they disappear when you swim in the cold ocean. They are two cold and retreat into the body for warmth as they need to remain at the right temperature to work at their optimum.
That should cure the boredom...
Runningbear