Sexual reproduction involves in the production of sex cells.

Sex cells are sperm and egg, they called together Gametes

The thing that make sexual reproduction different fron asexual reproduction it(sexual reproduction) involves two parent organisms. This gametes are produced through the process call Meiosis

Meiosis is a type of cell division that results in four daughter cells with half the number of chromosomes of the parent cell.

Sexual reproduction starts with the union(fuse) of this gametes in a process called Fertilization.

Fertilization is the process in sexual reproduction where the sperm and egg unite, resulting in the formation of a new organism. Thus new organism called zygote - fertilized egg.

This process can occur in both inside and outside in the female body. When it is inside we call it internal fertilization and on the other hand when it is outside we call external fertilization.

Let's go back to the gametes, female gamete(egg) are always larger than the male gamete (sperm). Female gametes are not mobile that means they can't move they are fixed in the female body.