Flowers contain the reproductive structures: stamens (male) and carpels (female). Stamens produce pollen grains, which contain two sperm cells, while carpels contain the egg cells. Seeds develop following pollination and fertilisation (fusion of the male and female gametes).

Each kernel in a cob of maize is the seed of a new individual, and although they all share a mother, they can each potentially have a different father. For this reason plant breeders need to protect the ears (the female inflorescence of maize) after a breeding cross, to make sure the female parent is only exposed to the pollen of the chosen male parent.