Sexual reproduction occurs by the fusion of gametes which in. During reproduction, gametes from each parent fuse together to males are the spermatozoa and ova in females. Each gamete contains half of the usual number of chromosomes so are haploid, they contain. All other cells of the body are said to be diploid because they contain 46 sets of chromosomes and are referred to as 2n chromosomes. produce a new cell. This new cell, a zygote, is diploid because it has received one set of chromosomes from each parent. chromosomes are called autosomes. Autosomes are the chromosomes that determine everything except an individual"s sex. Sematic cells, all cells of the body except gametes contain two sets of 22 autosomes. Each autosome in a pair carries the same complement of genes and is so said to be homologous. The remaining one chromosome of the two sets of 23 chromosomes and diploid cells is the sex chromosome that determines an individual"s sex.