Actually they are the most effective form of contraceptive available today (other than abstinence).They have a 0.05% failure rate, whereas complete tubal sterilization (the most effective permanent preventative for women) also has a failure rate of 0.05% and an IUD has a failure rate of up to 0.08%. Even then most failures come from an incorrect insertion and a study of almost 3000 women who underwent a correct insertion achieved 100% effectiveness. So yea, I trust it. I trust it more than sterilization.