In what reproductive structures are sperm created? egg?

Testes are the structure in male organism where sperm cells are produced. The process in which sperm cells are produced called spermatogenesis. Ovaries are the structure in female organism where egg cells are produced. The process in which egg cells are formed is called oogenesis.

When sperm of male combine with egg of female, it produces a fertile zygote and this zygote turns into a new organism.