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A female animal, usually a calf, that is born as the twin of a male animal and is sterile because of having abnormal internal reproductive organs.

[Probably free-, of unknown origin + an element akin to Scots mart, ox or cow fattened for slaughter (as freemartins often are) (from Scottish Gaelic, from Old Irish), perhaps influenced by the name of St. Martin of Tours, because cattle were traditionally slaughtered and salted for winter use on Martinmas.]


(Veterinary Science) the female of a pair of twin calves of unlike sex that is imperfectly developed and sterile, probably due to the influence of the male hormones of its twin during development in the uterus
[C17: of uncertain origin]


(ˈfriˌmɑr tn)

a female calf that is born as a twin with a male and is sterile as a result of exposure to masculinizing hormones produced by the male.
[1675–85; orig. uncertain]
References in periodicals archive ?
Freemartin heifers are caused by circulation of male twin's hormones through the developing female foetus (Roberts, loc cit.
Anatomopathologic cytogenetic and molecular studies of the freemartin syndrome in cattle (Bos taurus).
Direct observation of hematopoietic progenitor chimerism in fetal freemartin cattle.
The female twin of a cow/calf pair is called a freemartin.
There are echoes of Huxley here, this time of the dystopian Brave New World, where consumption drives all human activity, sex is detached from notions of romantic love, fertility is "merely a nuisance," and the "guaranteed" sterility of freemartin females leads, as it does with Waugh's Clara, to "the slightest tendency to grow beards" (22).
The gonadal and phenotypic sexes of the freemartin can be explained in the following manner.
Freemartin (fre-mar-ten) A female calf twin born with a male calf that has a high likelihood of infertility and underdeveloped reproductive organs.