During which stage does the formation of gametes primarily occur?

The formation of gametes primarily occurs during meiosis, which is a specialized type of cell division that reduces the chromosome number by half, leading to the production of haploid cells. In humans and many other organisms, meiosis takes place in the gonads—specifically in the ovaries for females and the testes for males.

During this process, diploid germ cells undergo two rounds of division to create four non-identical haploid gametes, which are sperm in males and ova (eggs) in females. This is crucial for sexual reproduction, as the fusion of two haploid gametes during fertilization restores the diploid state in the resulting zygote.

Meiosis includes key processes such as crossing over and independent assortment, which contribute to genetic diversity in the offspring. Understanding meiosis is fundamental to concepts in genetics and reproduction, making it vital for studies in anatomy and physiology.

The other stages mentioned do not involve gametogenesis. Fertilization pertains to the union of gametes, organogenesis is the phase where organs are formed during embryonic development, and implantation refers to the attachment of the fertilized egg to the uterine wall.