This is called hermaphroditism. This allows the organism who has difficulty finding a suitable mate the chance to reproduce. Many hermaphrodites exchange sperm with a mate increasing the potential of producing offspring. Another form of sexual reproduction is parthogenesis. Parthogenesis is the development of an egg without fertilization.
Adults developed by parthogenesis are haploid.
Some social insects develop in this way. Sequential hermaphroditism occurs in some species. Here an animal can change it s sex. This reversal is connected with the age and size of the animal. Clams and some fish are able to carry out this process.