Homosexuality can refer to both sexual behavior and sexual attraction between people of the same gender or to a sexual orientation. When describing a sexual orientation, it refers to enduring sexual and romantic attraction toward others of the same sex, but does not necessarily involve sexual behavior. Homosexual behavior includes any sexual activity between people of the same sex, regardless of sexual orientation. Homosexuality is contrasted with heterosexuality, bisexuality, and pansexuality. While the term gay often refers to a homosexual man, it sometimes refers to homosexual people of either gender. Lesbian denotes a homosexual woman.
Homosexuality has been a feature of human culture since earliest history (see Homosexual relations through history below). In modern times it was not until the 19th century that such acts and relationships were seen as indicative of a type of person with a defined and relatively stable sexual orientation. Karl-Maria Kertbeny coined the term homosexual in 1869 in a pamphlet arguing against a Prussian anti-sodomy law. Richard Freiherr von Krafft-Ebing's 1886 book Psychopathia Sexualis popularized the concept.

In the years since Krafft-Ebing, homosexuality has become a subject of considerable study and debate. Viewed by some as a pathology to be cured, it is now more often investigated as part of a larger project to understand the biology, psychology, politics, genetics, history and cultural variations of sexual practice and identity. The legal and social status of people who perform homosexual acts or identify as gay or lesbian varies enormously across the world and remains hotly contested.

Homosexuality and psychology have a closely intertwined history. Since its inception, psychology has dealt with the issue of homosexuality and sexual orientation.
Several psychological studies have been carried out on the psychology of heterosexism and hatred of homosexuals (or homophobia). For example, one study found "lower degrees of anti-homosexual bias in people who know openly homosexual people on a personal basis.
What is homosexuality?
Homo is a Greek word for equal. Homosexuality is to have a preference for sexual relations with and feel attracted to persons of the same sex. Women who are homosexual are called lesbians.
Bisexual people don't have a preference for a sexual relationship with a certain sex, but feel attracted to both men and women.
So men with a preference for sexual relations with men and women with a preference for sexual relations with women.
First of all, it is important to correct the common misunderstanding that a person is either homosexual or heterosexual. Kinsey and his colleagues developed a scale to measure the extent of heterosexuality and homosexuality in individuals. It was thus claimed by Kinsey that some individuals are entirely homosexual in their orientation, others are bisexual, and others (the majority of people actually) are entirely heterosexual.
Bisexual people don't have a preference for a sexual relationship with a certain sex, but feel attracted to both men and women.
Distinction should be made between homosexual orientation and homosexual behaviour. Homosexual behaviour is fairly common in adolescence and some heterosexual individuals will engage in homosexual behaviour under certain circumstances when access to the opposite sex is prevented (schools, military service, prisons, etc.). The prevalence of homosexuality in adulthood is uncertain and is estimated between 7 % of men and 4 % of women.

No forms of homosexuality are illegal in Europe.
There is no need for a homosexual to seek psychiatric or psychological help unless there are other emotional symptoms associated with it (for instance, anxiety or depression, etc.), since homosexuality is not considered as a psychiatric disturbance.

What causes homosexuality?
To pose the question of what causes homosexuality is actually a judgment about homosexuals. If you ask for the causes of homosexuality you assume that this is a disorder which needs to be explained.
It is better to find out what influences and processes that determine sexual preferences, whether this is homosexuality, heterosexuality or something else.
Research today is dedicated to find influences and processes which determine a persons sexual preference. Sexual preference is assumed to be determined by physical (genes), psychological and social factors (environment).

Physical causes for the development of a sexual preference could be certain brain structures or hormones and research is now being done on a certain homo gene. Psychological causes and social factors could play a role. However, not enough is known about these causes for sexual preferences and there hasn't been enough research to say anything reliable about this.

What problems can a homosexual meet?
How homosexuals in a mainly heterosexual society discover their feelings and learn how to deal with them is summarized in the term "coming out". "Coming out" is to reveal their homosexuality to their surroundings. The term "coming in" is used for this integration in the homosexual culture. The development of the homosexual identity is of course individual but can shortly be summarized as follows:

Phase 1: Sensitization: the person becomes aware of their attraction to people with the same sex, this often happens before puberty.

Phase 2: Identity confusion: the person begins to realize that their feelings or behavior can be called homosexual. This may lead to confusion, feelings of insecurity, embarrassment, guilt and isolation, but when the person realizes that there are others with the same feelings the negative feelings and the idea of isolation may be reduced or disappear.

Phase 3: Acceptance of their identity: this phase often happens during late adolescence. In this phase their homosexuality is tolerated, but not yet accepted. They begin to see them self as homosexuals and present them self to others as such. This makes it possible to meet other homosexuals and discover the homosexual culture. The experiences that they have at this stage are important for dealing with homosexuality later. Contact with other homosexuals is important for discovering the positive sides of homosexuality and learning how to deal with the opinions of non-homosexuals. The third phase ends when they inform others generally of their homosexual feelings.

Phase 4: Commitment: in this phase homosexuality is experienced as a more self-evident part of the personal identity. They accept their homosexual feelings and are at ease with this identity and role.

Negative feelings that have been taught and partly familiarized with don't always disappear. Depression, alcohol abuse, attempts to commit suicide and other psychological problems may be consequences of not dealing effectively with their identity.
For parents it is not always easy to deal with homosexual children. Expectations should be adjusted and accepted. It is important to have an open attitude towards them. Indicate that it is hard to talk about this problem, but as parents you want to accept their feelings and support them as much as possible.

How can people react to homosexuality?
Many find it important to group people: heterosexual, homosexual, bisexual, etc. Why is such a division so important socially? Language is a way for people to communicate.
During adolescence young people are still 'allowed' to experiment, but after this most people know their sexual preference and behave accordingly.
Heterosexuality is the basis of our society. Most people are or feel heterosexual and the heterosexual family is seen as the ideal way of living. Because of this we distinguish between people who can and who can't satisfy this norm.
Sometimes we don't know how to treat people with any other sexual preference than the average. This is because we find it hard to imagine the feelings of a person with another sexual preference.
Parents of homosexual or bisexual children may be disappointed because they have other expectations of their child or they are embarrassed by the child's behavior. This can lead to discrimination, depressed feelings, fights, aggression, breaking friendships, etc.

Is there a treatment for homosexuality?
The question of whether there is a treatment for homosexuality suggests that homosexuality is seen as a disease. It is better to ask if there are possibilities for homosexuals and their surroundings to accept this sexual preference and learn how to deal with it.