Meiosis is the splitting of chromosomes pairs in the formation of sex cells. Sexual reproduction cannot work unless eggs and sperm each contain precisely half the genetic information of normal body cells. The union of two halves restores the full amount of genetic information, while the mixing of genes from two parents in each offspring allows the  evolutionary genetic variability.

Errors in splitting often occur. On rare occasions, such error are harbingers of new evolutionary directions. In most cases, they simply lead to misfortune for the offspring. The most common meiotic error is  called non-disjuction: the chromosome fails to split. The egg cell or the sperm cell will bring a pair chromosome instead of . A child from the union of a normal sex cells with one containing an extra-chromosome (by non disjunction) will cary three copies of that chromosome. This anomaly is called trisomy.

In humans, the chromosome 21 suffers non disjunction at remarkably high frequency. About 1 in 600 to 1 in 1000 newborn babies carry an extra chromosome 21, a condition called “trisomy 21”. These children suffer milf to sever mental retardation and have a reduced life expectancy. They exhibit, in addition, a suit of distinctive features, including short and broad hands, a narrow high palate, rounded face and broad head, a small nose and thick and furrowed tongue. The frequency of trisomy-21 rises sharply with increasing of maternal age.

The common designation for trisomy-21 is Mongolian Idiocy, Mongolism or Down’s Syndrome. Why this condition was designated Mongolian Idiocy? 

Most of the children with trisomy-21 have a small but perceptible epicanthic fold, a typical feature of an oriental eye, and some have a slightly yellowish skin. Theme minor and inconstant features led Dr. John Langdon Haydon Down to compare them with orientals when he described the syndrome in 1866. But there is far more to the story of Down’s designation than a few occasional, misleading and superficial similarities; for it embodies an interesting tale in the history of scientific racism.

Few people who use the words Mongolian and Idiot know the very rooted meaning of these terms. Idiot one referred to the lowest grade in threefold classification of mental deficiency:

  • idiots could never master spoken language;
  • imbeciles, a grade above, could learn to speak but not to write;
  • morons, slightly feeble-minded (from the greek “moron” meaning foolish).

Goddard, one of the three major architects for the rigidly hereditarian interpretation of IQ tests, believed that his classification of metal worth could be simply extended for ranking humans races and nationalities with souther and eastern European immigrants on the bottom and old Americans on the top. Indeed, after Goddard institutes IQ test for immigrants upon their arrival at Ellis Island, he proclaimed more than 80% of them feeble-minded and urged their return to Europe.

Dr. Down was medical superintendant of the Earlswood Asylum for Idiots in Surrey when he published his “Observations on an ethnic classification for Idiots” in the London Hospital Reports for 1866. In a mere three pages, he managed to describe Caucasian “idiots” that reminded him of African, Malay, American Indian and Oriental peoples. Of these fanciful comparisons, only the “idiots who arrange themselves around the Mongolian type” survived in the the literature as a technician designation.

The pervasive racism at the age of Dr Down polluted the biological and social field, biasing the medical and scientific literature.

In Down’s day, the theory of recapitulation embodied a biologist’s best guide for the organization of life into sequences of higher and lower forms. This theory, often expressed by “ontogeny recapitulates phylogeny“, held that higher animals, in their embryonic development, pass through a series of stages representing, in proper sequence, the adults forms of ancestral-lower creatures. Thus, the human embryo first develops gill slits, like a fish, later a three chambered heart, like a reptile, still later a mammalian tail. Recapitulation provided a convenient focus for the pervasive racism of white scientists : they looked to the activities of their own children for comparison with normal, adult behavior in lower races.

They attributed many anomalies of form or behavior to “throwbacks” or “arrests of development“. Throwbacks, or atavism, represents the reappearance in adults of ancestral features that had disappeared in advanced lineages. Cesare Lombroso, the founder of “criminal anthropology”, believed that many lawbreakers acted ny biolgical compulsion because a brutish past lived again in them. He sought to identify “born criminals” by “stigmata” of apish morphology: receding forehead, prominent chin, long arms.

Arrests of development represents the anomalous translation into adulthood of features that arise normally in fetal life but should be modified or replaced by something more advanced or complicated. If a Caucasian suffers development arrest, he may be born at lower stage of human life (lower races).

Therefore Dr. Down scrutinized his charged for features of lower races, just as 20 years later Cesare Lombroso would measure the bodies of criminals for signs of apish morphology. Down described his search with obvious excitement: he had, or so he thought, established a natural and causal classification of mental deficiency. He wrote:

The more serious the deficiency, the more profound the arrest of development and the lower the race represented

He found  idiots of the Ethiopian variety, Malay variety, Indian American variety. And mounting the scale of races, he came to the rung below Caucasian “the grest Mongolian family”.

Dr. Down wrote:

A very large number of congenital idiots are typical Mongols. So marked is this, that when placed side by side, it is difficult to believe that the specimens compared are not children of the same parents”. The Down’s syndrome was classified”

Down did not confined his description to supposed anatomical resemblances among oriental people and “Mongolian Idiots”. He also pointed to the behavior of his affected children. He wrote

They have considerable power of imitation, even bordering on being mimics

It requires some familiarity with the literature and the racism of that time to read the meaning of of these words. The sophistication and complexity of oriental culture proved embarassing to Caucasian racists, especially since the highest refinements of Chinese society had asisen when European culture still wallowed in barbarism. Caucasians solved the dilemma by admitting the inttellectual power of orientals, but attributing it to a facility for imitative copying rather than to innovative genius.

Dr. Down concluded his description of child with Mongolian Idiocy:

The boy’s aspect is such that it is difficult to realize that he is the child of Europeans, but so frequently are these characters  presented, that there can be no doubt that these ethnic features are the result of degeneration“.

Down’s theory lost its rationale when physician detected it both in orientals themselves and in races lower than oriental (in the Dow’s classification), even in chimpanzees.



  • Image taken from
  • “The Panda’s Thumb” by Stephen Jay Gould (W.W. Northon & Company,)