Question
Sex determination in an unborn baby:
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Answer
The sex of a baby is determined by the type of male gamete that fuses with the female gamete. All human beings have $23$ pairs of chromosomes in their nuclei. Out of these $23$ pairs, the last pair is known as the sex chromosome. The human males have $23$ pairs of chromosomes including $XY$ sex chromosomes. Therefore, the male gamete has 22 chromosomes and either an $X$ or $Y$ sex chromosome. Male gametes can be of two types: $22 + X or 22 + Y$ Females have $23$ pairs of chromosomes including $XX$ sex chromosomes. Therefore, their gametes can only have $22$ chromosomes and one $X$ sex chromosome. Type of female gametes: $22 + X$.
Thus, as the mother provides only $X$ chromosome, the sex of the baby is determined by the type of male gamete ($X$ or $Y$) that fuses with the $X$ chromosome of the female.
Thus, as the mother provides only $X$ chromosome, the sex of the baby is determined by the type of male gamete ($X$ or $Y$) that fuses with the $X$ chromosome of the female.
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