Many reptiles have temperature-dependent sex determination: the temperature embryos experience during their development determines the sex of the organism.
In some turtles, for example, males are produced at lower incubation temperatures than females; this difference in critical temperatures can be as little as 1-2 °C.
Humans sometimes engage in behaviors that do not include the penetration of sexual organs, such as oral intercourse or anal intercourse or by non-sexual organs (fingering, fisting).
These behaviors are sometimes included in the definition of sexual intercourse.
It involves a man and woman having sex without birth control until the man ejaculates, or releases, semen from his penis into the woman's vagina.
The semen, containing sperm (which is made in his testicles), moves to the Fallopian tubes, and if it finds an ovum on its way, it will try to fertilize it. Certain species of animals also have sex for other purposes than to bear offspring.
Sequential hermaphrodites may produce both types of gametes over the course of their lifetime, but at any given point they are either female or male. Ferns which grow in soil which has previously supported hermaphrodites are influenced by hormones remaining to develop as male.
Sex is a type of reproduction common among living things. In humans, the sex of a person depends on what sex chromosomes that person got from his or her parents.
Sex is used by plants and animals, and also by fungi and various single-celled organisms. A woman's ovum (egg cell) contains one X chromosome.
It usually needs two individuals which are different sexes from the same species. A man's sperm contains either an X or a Y chromosome.
It works by combining genes from more than one source. When a sperm and ova combine to form a fertilised egg, the baby may get either of these chromosomes from its father.
Some fish change sex over the course of their life.