The term homosexuality has acquired several meanings over the years, but it originally referred to a persons sexual desired only towards the same sex. Much of the misunderstanding people have about homosexuality stems from old ideas that homosexuals are mentally ill but this is not the case as this part of a humans make up is hard wired into them at the genetic level. The term 'gay' can refer to all homosexuals be that man or woman, however the term lesbian refers exclusively to homosexual women.
A study of Homosexuality
Homosexuals are often broken down into three social models, the first of which is Egalitarian or a relationship that has two partners who play the same accepted rolls that society places on a person of that sex.
The second is gender structured, and involves each partner playing a different gender role. You can see this in between men in the Mediterranean Basin, the Middle East and Central and South Asia, and in North America, this is best represented by the butch/femme practice.
Last we have an Age structured relationship made up of two partners of different ages. Usually they are at least one generation apart in age and can be seen among the Classical Greeks or those acts engaged in by novice Samurai, with more experienced warriors.
How common is Homosexuality
Current estimates on the number of homosexuals (not including bisexuals) in Western countries, range in the area of 1 - 10%. However, many who are homosexual may not be open about it in public and are therefore difficult to count.
In the Middle East and Central Asia, where gender- and age-structured relationships are normal, male homosexual practices are known to be widespread and engaged in by many individuals who do not regard themselves as homosexual.