Homosexuality can refer to sexual attraction or love a person of the same gender, sexual behavior between organisms of the same sex or a sexual preference for an organism of the same sex. In describing the latter referred to a conservation sexual and romantic attraction to their own sex, but not necessarily to sexual behavior. Homosexuality is contrasted with heterosexuality (attraction, behavior or sexual preference between opposite sex), bisexuality (both sexes) and asexuality (no sex).
Homosexual behavior occurs among many animals besides humans, especially among social animals.
Lesbian refers to love between women. The concept arose from the poetry of the Greek poet Sappho of Lesbos , who expressed strong romantic feelings towards other women.
Homosexuality in animals
Animals also has documented evidence of homosexual, bisexual and transgender behaviors. Such behaviors include sexual acts, mating rituals, affection, pair bonding and parenting.
A research review done in 1999 by biologist Bruce Bagemihl shows that homosexual behavior has been observed in close to 1500 species, from monkeys to intestinal worms, and is well documented for 500 of them. Animal sexual behavior takes many forms, including in the same species. Reasons for and implications of these behaviors have not yet been fully clarified, as most species still need to be studied further .
According Bagemihl, animals have sex with much greater sexual diversity – including homosexual, bisexual and non-reproductive sexual acts. Recent research suggests that different forms of same-sex sexual acts are throughout the animal kingdom.
A new review in 2009 of existing research showed that same-sex sexual behavior is a nearly universal phenomenon in the animal kingdom, common in all species.
The natural occurrence of homosexuality in the animal world has been used as an argument for homosexuality in humans is natural, but that conclusion has been deemed controversial by conservative religious groups.
Many experts in the field are cautious to draw far-reaching conclusions about people based on the results of research on animals. The research on homosexual behavior among animals also contradicts Thomas Aquinas’s thesis on “Naturam Peccatum contra” ( ” sin against nature “), which has been established since the Middle Ages in Christendom . Whether this contradiction Aquinas thesis has logical or ethical implications are also a source of debate and some argue that it is illogical to use animal behavior to justify what which is or is not morally humans.