Humanoid " " All humanoid life has a similar genetic pattern . " " As generally understood by the , a humanoid was an intelligent , bilaterally symmetrical , biped al lifeform in possession of an upright posture , two arms , two legs , hands , feet , one thorax , a neck , and a head with a brain located in it . They were generally mammal ian and originated on class M planet s . It was common for them to have two to four sex es . Among the many humanoid species known throughout the Milky Way Galaxy were Andorian s , Betazoid s , Bolian s , Bajoran s , Cardassian s , Hirogen , Klingon s , Human s , Romulan s , and Vulcan s . Ancient origins . Despite the vast distances separating their homeworld s , many humanoid species have been found to share a remarkable commonality in form and genetic coding . These similarities were believed to be evidence of a common ancestry , an ancient humanoid species , who lived in our galaxy ' s distant past some four billion years ago . To preserve their heritage , this species apparently seeded the primordial oceans of many potentially hospitable planets with encoded DNA fragments . The genetic information incorporated into the earliest lifeforms on those planets and through pre - programmed mutations caused by a genetic template , directed evolution toward a physical development similar to their own . Because of this controlled mutation mechanism , most habitable planets in the galaxy evolved with many physically similar species ( for example fish , trees , dog s , insect s ) , and on many of those worlds with at least one sentient species with a humanoid configuration . Most of these humanoids were even interfertile with each other . Anatomically , a significant percentage of those lifeforms were outwardly indistinguishable from Humans , right down to such morphological minutiae as the same racial phenotypes , hair distribution patterns , fingernails , and cartilaginous folds of the nose and ear s . The reason they were so astonishingly similar to the Human race was because the " Human form " represents the basic way that evolution most likely takes for the dominant mammalian race on an average class M planet under the influence of the genetic codes and the other humanoid races ( for example Klingons , Cardassian s , Vulcans ) developed under very specific and usually unique environmental conditions . Humanoid progenitors . In one of the most remarkable scientific detective stories in history , archaeologist Richard Galen of Earth uncovered the similarities between certain DNA sequences in lifeforms from widely separated planets . He discovered that these DNA sequences were a puzzle deliberately left behind by these ancient progenitors . The DNA sequences , when assembled by protein - link compatibilities , formed an ingenious computer program , a message of peace and goodwill to their progeny . This message , assembled in 2369 in an unprecedented example of interstellar cooperation , was a confirmation that many humanoid species in this galaxy are indeed members of the same family , despite their significant differences . ( ) The humanoid form was further distributed by species such as the Preservers , a super - race which passed through the galaxy rescuing primitive cultures in danger of extinction , and seeding them on other worlds where they could be allowed to grow and thrive . In addition , when the non - corporeal lifeform Sargon was encountered by the crew of the in 2268 , he implied that some humanoid races , such as the Vulcans , were the product of ancient colonization by his race before they lost their physical forms . ( ) Taxonomy of humanoids . The Xindi did not apply the term in the same way as many of the other social groups in the Milky Way Galaxy . For them , " humanoid " was a word that only applied to the Xindi - Primate s , despite the fact that the Arboreal s and the Reptilian s also generally met the criteria . ( ) Starfleet developed a classification system for humanoids which included at least five variations including class 3 humanoid s , such as the Vidiian s , and class 5 humanoid s , such as the Vhnori . Background information . The TNG Season 1 " " states that " " Humanoid in our series means a life form which is similar to humans . ( Two legs , arms , head , etc . ) In the past , we have met humanoid aliens , such as Klingons , Vulcans and Romulans . " "