Homosexual refers to a person who is attracted to members of the same sex exclusively. (As opposed to a bisexual which are attracted to both sexes.)
In the field of psychology when writing under American Psychiatric Association (APA) guidelines for scientific journals a writer must refer to homosexuals as "gay" or "lesbian" depending on gender. This is a result of the negative connotation that in recent years has surrounded the more clinical sounding word homosexual.
In addition the APA which writes the Diagnostic and Stastical Manual Fourth Edition (DSM-IV) declassified homosexuality as a psychological illness in 1973. In 1975 the American Psychological Association followed suit and declassified homosexuality as an illness. In the past 35 years there has been much objective scientific research which shows that being gay or lesbian is not associated with emotional or social problems.
Gay and lesbian individuals are able to form life long partnerships. Many gay and lesbian couples raise children and form cohesive family bonds.
Currently it is illegal to have consensual gay sex in four of the 50 United States. Those four states are Texas, Missouri, Oklahoma, and Kansas. (Ed. note: See Lawrence v. Texas) On the federal level gays and lesbians have no legal recognition of their relationship. The result of this lack of recognition is that over 1000 right and protections extended to heterosexual married couples are denied to homosexual couples. In addition immigrating homosexuals are not permitted immigration rights for their partners that many countries around the world extend to gay domestic partners.
Internationally in April 2001 the Netherlands became the first country to permit gay and lesbian couples to marry and receive all the rights, protections and benefits that flow from it. Many European countries are moving towards allowing gay marriage.