'The sex of the children is determined by what they inherit from their father and not the mother.' Justify.

Sex determination:

1. Sex in humans is determined by the XX-XY type of sex determination.
2. Each cell of the human body comprises 23 pairs of chromosomes.
3. The human females are homogametic as they bear 44 autosomes (A) and two X-chromosomes in diploid cells. They produce 100% similar gametes, each of them containing 22 autosomes and one X-chromosome.
4. Human males are heterogametic because they produce two types of gametes (sperms), 50% bear 22 autosomes and one Y-chromosome and the rest 50% bears 22 autosomes and one X-chromosome.
5. When the egg is fertilised by sperm bearing Y-chromosome a male offspring will result and if, by sperm bearing X-chromosome, female offspring will result. The two sexes will be produced in equal numbers in the ratio of 1: 1.
6. Thus, it is proved that the sex of the children is determined by their father.
7.