Sex
* acts between a man and a woman, as well as between two men.
* creates variation in offspring.
* is an activity
  - used by plants and animals, and also by fungi and various single-celled organisms
* means whether someone was born with a male or female 'body'.
* method of reproduction which is widespread among living things.
+ Bisexual pornography: Pornography :: Human sexuality
  * As most pornography is marketed to men, most bisexual porn is advertised to straight or bisexual men. Very few customers of bi-porn say they are gay. Sex acts between a man and a woman, as well as between two men. A common way that these are shown in a single scene is with one woman and two men performing together.
+ Nightingale: Luscinia :: National symbols of Iran :: Birds of Turkey :: Birds of Pakistan :: Passeriformes
  * The Nightingale is slightly larger than the European Robin, at 15-16.5 cm length. It is plain brown above except for the reddish tail. It is buff to white below. Sexes are similar.
+ Sex determination: Classical genetics :: Developmental biology :: Cell biology :: Biological reproduction
  * Sex determination' is a process of development by which the sex of an individual is settled. Sex is a method of reproduction which is widespread among living things. It requires two individuals of the same species.
  * Sex' is a type of reproduction common among living things. It always needs two individuals, usually of the same species. Sex is used by plants and animals, and also by fungi and various single-celled organisms. It works by combining genes from more than one source. A dictionary of genetics', 7th ed.
+ Sex, Evolution
  * Sex creates variation in offspring. If there are traits that give an advantage to the organism, they spread more easily. Traits that give a disadvantage tend to be removed quickly.
+ Sexual arousal, Animals: Reproductive system :: Human sexuality
  * Like humans and some chimpanzees, dolphins use sex for reasons other than procreation. Sex is as frequent as it is casual, a social tool used to strengthen and maintain bonds.
+ The Red Queen, The evolution of sex: Biology books :: Co-evolution
  * Sex is an evolutionary puzzle. In most sexual species, males make up half the population, yet they bear no offspring directly and generally contribute little to the survival of offspring. In birds and mammals that idea seems less true. In human paleolithic populations, males were no doubt vital for hunting and protection. Many bird species rear the young jointly. However, most invertebrate species are not raised by parents at all, with larvae developing amongst the plankton.
+ Transgender, Definitions

### sex:

Carnal knowledge
* is sex
* means sex.

### sex | free love:

Adultery
* can be a healthy way of dealing with stress in a marriage.
* causes pain
  - rage
* creates pain and distress and is the wrecker of families.
* destroys marriages.
* devastates whole families as it crushes our mate and cripples our children.
* is free love
* leads to the death of our relationships within our family.
* occurs when a married man or a woman has a relationship with another person.
* refers to marital infidelity.
* turns millions of father's hearts from their children.

Incest
* is sex
  - the ultimate form of inbreeding.
  * In many societies, it is forbidden by law and religion. Children that result from incest are more likely to have birth defects. Incest is the ultimate form of inbreeding. Any offspring from an incestuous relationship is called an 'inbred', but this word is sometimes considered offensive