This assay is useful for evaluation of men with signs and symptoms of possible Hypogonadism like loss of libido, erectile dysfunction, gynecomastia & infertility. It is also useful in evaluation of boys with delayed or precocious puberty. The assay can be used to monitor anti- androgen therapy as in prostate cancer, precocious puberty & male to female transgender disorders. It helps to evaluate infants with ambiguous genitalia or virilization. The assay can serve as an adjunct in the diagnosis of androgen secreting tumors.
Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition.  The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression.  Thus it is the challenge of competition among males of the species that facilitates aggression and violence.  Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels.  The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males. 
Again, though, there is ample research that megadosing iodine can cause problems. For example, a number of studies that show high iodine levels in the diet can really causes problems. One study of Peace Corp volunteers in Ghana found that 44% had goiter from excessive iodine in their water filters. When this was taken care of, their "mean serum iodine decreased from 293 Â± 306 to 84 Â± 46 Î¼g/liter."  And, correspondingly, their TSH dropped from a high to a very sound mU/liter .