Explain how the sex of the child is determinated at the time of conception in human beings.
Sex of a child: Every body cell of humans contains 23 pairs of chromosomes. Out of these 23 pairs, first 22 pairs or 44 chromosomes do not determine sex on an individual and they are called autosomes. Remaining one pair determines sex of individual. The last pair is called sex chromosomes. They are represented as X and Y. Male gametes in humans have 22 autosomes and either an X or a Y sex chromosomes where as the females have XX sex chromosomes, along with the 22 autosomes. It means that their gametes can only have an X sex chromosome”. So, off springs sex of the child is determined by type of sperm (containing an X or a Y sex chromosome). That fuses with egg cell (containing an X chromosome) at time of conception in human beings. When X gamete of male fuses with X gamete of female, then offspring will be female. Whereas if Y gamete of male fuses with X gamete of female, then offspring will be male.