I have ben playing FO3 since it came out i have found out almost every thing about it. i could tell you about the super mutants there are not men they are women and the men i think are the centaur. i really could not find out what happened to the men all i could find was what happened when the women took this modified FEV virus. it was a test that was in vault 87 they tested this virus on 2 males and 3 females for 24 hour observation. these experiment were funded by vault-tec and military from mariposa. back to this experiment after 3 day the females were undergoing some severe physical changes. losing most of their visible female indicators and transforming to an almost asexual state. they are also seeing increased upper body strength and muscle formation in line with males. the men went under a similar transformation. they had a minor setback all the fev subjects started to have loss of brain function and were unable to sustain basic bodily needs. at ten days they started to get more resilient and thicker skin. after 14 days the subjects began to exhibit sever bouts of rage and anxiety. that is what i have found out about super mutants so far if you want to read more go look for your self the terminal is in the test lab of vault 87. i am still trying to find out what the men turned in to but i believe they are the centaurs