  Using the result that an electric charge - magnetic charge system carries an internal field angular momentum of $e g / 4 \pi$ we arrive at two restrictions on magnetic monopoles via the requirement of angular momentum quantization and/or conservation. First we show that magnetic charge should scale in the opposite way from electric charge. Second we show that free, unconfined monopoles seem to be inconsistent when one considers a magnetic charge in the vicinity of more than one electric charge. 
Restrictions on Magnetic Charge from Quantized Angular Momentum