A global clinical trial has been conducted to test the effectiveness of hormonal contraception for men.  As covered in a recent story by health editor Anna Almendrala of the Huffington Post, the trials have shown some signs of being able to suppress sperm production in nearly 96 percent of men who completed the study.  Even with the high success rate, the participants of the trials did experience a high number of adverse effects from the shots. Scientists in the study say they will need to re-formulate the injections or experiment with different injection protocol before testing it again.