13/12/2011 17:18 GMT | Updated 12/02/2012 05:12 GMT

As Natural As Life Itself

Male mosquitos are as benign as butterflies. They have fleshy lips with hairy antenna and fly around gathering pollen. It's the females who are the horrors. Their lips are hypodermics, made for sucking blood and injecting itch-making saliva. As a result, when mosquitos fall in love they don't do a lot of kissing. But what if they're both males, with those big fleshly lips?

Homosexual behaviour has been observed in more than 500 species of animal, including nearly all common insects. If you're a bedbug or a club-tailed dragonfly or a flour beetle, then just like a human being you have a one in 10 chance of fancying a member of your own sex. If you're a bean weevil, a migratory locust, a blueberry bee, or even an ordinary house fly, you could turn out as queer as a coot (as can a coot itself, of course).

In China, at Harbin Zoo, a pair of male penguins prepare their nest each year for an egg that never arrives. When it doesn't, they steal eggs from other penguins. So this year their keepers gave them an egg laid by an inexperienced female. And they're turning out to be perfect parents.

In the zoo business that doesn't surprise anyone; there have been gay bird couples all over the world. In Coney Island aquarium, Wendell and Cass, a pair of male penguins, have been living happily together for years. At the Jerusalem zoo, three years ago a pair of male vultures, Dashik and Yehuda, reared a baby vulture chick. And at Slimbridge in England, two male flamingos, Carlos and Fernando, have for five years performed the same courtship dance as their heterosexual neighbours, then stolen their eggs to rear as adopted children.

No question, homosexual zoo animals behaving in a loving way is one more thing that has helped whittle away prejudice against homosexuality. But for the full picture of homosexual behaviour in animals, we should look in the wild. Apart from insects and birds, every known mammal is at it too, from elephants to bison to killer whales to polar bears, though not always as prettily as a pair of male penguins with an egg.

Amazon river dolphins of both sexes use their snouts and flippers to indulge in genital rubbing without regard to gender. For sexual penetration males sometimes use another male's blowhole, which is the equivalent of its nostrils. And for the ladies, there's a technique developed by bottlenose dolphins. One female inserts her beak into the genital opening of the other female, then swims gently forwards.

Male giraffes are unstoppably gay. 94% of penetrative mountings are male to male, with a great deal of necking going on beforehand. Hyenas, on the other hand, are rampantly lesbian. The females have a strange vagina that comes to a point and grows hard, which they use to mount other females.

Elephants too engage in same-sex relationships, including mounting and orgasm, but always preceded with trunk intertwining, kissing, and placing trunks in each other's mouths. And then there's the sex-mad Bonobo - a 100% bisexual chimpanzee that resolves all its quarrels with sexual activity. (And never stops quarelling.)

To those who are bigots (popes, mullahs, Nigerian bishops, and Republican presidential candidates), homosexuality in animals probably seems as distasteful as in humans. But there's one thing they can't deny - it shows that far from being "a sin against nature" homosexuality is as natural as life itself. Around one in 10 of us are born gay, about the same number as are born beautiful, ugly, tall, or short. Homosexuality doesn't require people to be tolerant of it. Just ignore it. It's no different from someone having blue eyes or being a redhead. It's how nature made us. And it was wonderful to hear last week that the United States has offically recognised that fact.

President Obama has ordered US agencies abroad "to use foreign aid to fight for gay rights". And Hillary Clinton told an audience of diplomats in Geneva, "Gay rights are human rights". Countries receiving American foreign aid, if they legislate against gays, lesbians or transexuals (or even make things difficult for them), may find their aid cut off.

Until the 1990s, US immigration frequently turned people away simply for being homosexual. To have come from there to here in 20 years is amazing. For President Obama it's an extraordinary step to take the year before an election. No doubt he was somewhat reassured by hearing that 60% of Americans now think that gays should have all the same rights as straights. But he still needs to be thanked.

So thanks Pres! And Hillary too. And all those nice zoo birds who make being gay look so pleasant and natural.