Final answer:
A child has the same number of chromosomes as each parent because the sperm and oocyte, which are haploid with 23 chromosomes each, combine during fertilization to create a diploid zygote with 23 pairs of chromosomes.
Step-by-step explanation:
A child has the same number of chromosomes as each of his parents because the gametes that combined when that child was conceived each contained half the number of chromosomes. Gametes are haploid cells, meaning they have only one set of chromosomes, which is 23 in humans. During sexual reproduction, a sperm cell from the father and an oocyte from the mother combine in a process known as fertilization to form a zygote.
The zygote is then diploid, with two sets of chromosomes, one from each parent, totaling 46 (23 pairs). This perfect pairing of chromosomes ensures genetic continuity and the inheritance of traits from both parents. Homologous chromosomes in these pairs contain genes for the same traits, although the specific alleles (versions of a gene) may vary between the two parents.