Question

Free Martin is due to
A) Sex reversal by gene
B) Environmental control of sex
C) Hormonal control of sex
D) Sex determination by chromosome

Answer 1

Hint:Free Martin is a female calf which is born as a twin with a male and is sterile as a result of exposure to masculinizing hormones created by men.

Complete answer:
Infertility in the female twin-born cattle to a male is caused by this disease. When a twin of a heifer (a cow that has not borne a calf, or has borne only one calf) shares the uterus with a bull foetus, the placental membranes that link the dam with the foetus are also shared. Around the fortieth day of pregnancy, a joining of the placental membranes occurs, and after that the fluids of the two foetuses are mixed.

This facilitates the exchange of blood and antigens that hold characteristics that are unique to each heifer and bull. When these antigens blend, they influence each other in a way that allows each to evolve with the characteristics of the other sex. While the male twin is only affected by decreased fertility in this case, the female twin is fully infertile in over ninety percent of the cases.

The heifer's reproductive tract is severely underdeveloped due to the transfer of hormones or the transfer of cells and often also includes certain components of the reproductive tract of a bull. Genetically, a freemartin is female, but has several characteristics of a male. Freemartin's ovaries do not mature correctly and remain very thin.

Thus the correct answer is option (C) i.e, ‘Hormonal control of sex’.

Note:When vascular connections form between the placentas of developing heterosexual twin unborn babies, a freemartin occurs. Freemartinism has not been proposed to occur in humans because the pathogenetic effects of vascular anastomoses vary from sex discordant, monochorionic twins between humans and cattle.