Q. 53.7( 3 Votes )
In human beings, the statistical probability of getting either a male or female child is 50 : 50. Give a suitable explanation.
Human beings have 23 pairs of chromosomes. The 22 pairs are called autosomes are similar in males and females. The two chromosomes (23rd pair) that determine the sex of the unborn baby are called sex chromosomes named X chromosomes and Y chromosomes.
A female has two X chromosomes (22+XX), while a male has one X and one Y chromosome(22+XY). The gametes (egg and sperm) have only one set of chromosomes. Thus, all the gametes produced by females have only the X chromosome (22+ X) while male produced two types of gametes, half gametes have X chromosomes (22+X) and half gametes have Y chromosomes (22+Y).
Therefore, the possibility of fertilization of egg (22 + X) with the sperm having (22 + X) chromosome to have girl child is 50%. Likewise, there is 50% possibility that egg is fertilized with sperm carrying (22 +Y) chromosome to have male child.
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