How is sex determined in human beings?

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Human beings exhibit male heterogamy. In humans, males $(XY)$ produce two different types of gametes, $X$ and $Y$. The human female $(XX)$ produces only one type of gametes containing $\mathrm{X}$ chromosomes. The sex of the baby is determined by the type of male gamete that fuses with the female gamete. If the fertilizing sperm contains $\mathrm{X}$ chromosome, then the baby produced will be a girl and if the fertilizing sperm contains $Y$ chromosome, then the baby produced will be a boy. Hence, it is a matter of chance that determines the sex of a baby. There is an equal probability of the fertilizing sperm being an $\mathrm{X}$ or $\mathrm{Y}$ chromosome. Thus, it is the genetic makeup of the sperm that determines the sex of the baby. (figure)

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Similar Questions

$A$ : $XO$ type sex determination is found in large number of insects.
$R$ : Some of the sperms bear the $X-$chromosome whereas some do not

Match the items of column $I$ with column $II$

Column $I$ Column $II$
$(a)\; XX-XO$ method of sex determination  $(i)$ Turner's syndrome
$(b)\; XX-XY$ method of sex determination  $(ii)$ Female heterogametic
$(c)$ Karyotype$-45 $ $(iii)$ Grasshopper
$(d)\; ZW-ZZ$ method of sex determination  $(iv)$ Female homogametic

Select the correct option from the following

  • [NEET 2019]

In our society a woman is often blamed for not bearing male child. Do you think it is right ? Justify.

While solving the problem of sex determination in large number of insects, it was observed that

Assertion : In humans, the gamete contributed by the male determines whether the child produced will be male or female.

Reason : Sex in humans is a polygenic trait depending upon a cumulative effect of some genes on $X-$ chromosome and some on $Y-$ chromosome.

  • [AIIMS 2015]