Freemartin

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Freemartin

(Science: veterinary, zoology) a condition occurring in dizygotic twins of different sexes in cattle, where an imperfect masculinised sterile female twin calf is born with a male.

this results from twin foetuses of opposite sexes in which the chorionic blood vessels become fused at an early stage of embryonic development, with the result that the hormones of the male twin are conveyed in the circulation to the female twin and influence its sexual development.

Both calves are blood Cell chimeras with immune tolerance, due to interchange of cells in utero.

Freemartins are a type of hermaphrodite with underdeveloped uterus, enlarged penis-like clitoris, and, sometimes, structures resembling the ductus deferens and seminal vesicles.