Sex is fun, but that’s not why we do it.
Jason John 2006
The evolutionary story of sex, with Christian reflection. This has been reworked many times, most recently I read it at an Adelaide Feast forum on spirituality and sexuality.

Sex is fun, but that’s not why we do it,
It’s only fairly recently that evolution grew it!
Still, I hope we’d all agree, when all is said and done,
That we like sex- sex is fun.

Of course, most creatures of Earth don’t even do it at all
They just split in half and then off they crawl
Then homosexuality was the first revolution,
There was only one gender for most of evolution.

Now we have genders, but not just two-
Some species have dozens.  Yes, it’s true!
Then we have all those whose gender bends
They switch back and forth- it never ends!
Fish girls become boys become women become men
A cycle repeating again and again.

Even when our gender stays fixed
Things can still get a little mixed:
XO, XX, XXX, XXXX, XXXXX
(that’s just the female sex!)
Also XY, XXY, XXXY, XXXXY, XYY
Yes all kinds exist on the male side.

And if you think that’s a little absurd-
The whole thing is reversed in those feathery birds!
I am an XY, a boy bird’s a ZZ
And there may be more we don’t know about yet!

Sea sponges can have sex, or do it alone,
Yes, on a whim they can mate, or clone.
Of course when they have sex there is no penetration
They just squirt it all out and hope for fertilization.
Those sponges have orgies to an unheard of degree,
So shut your mouth when you swim in the sea!

Creatures that do penetrate usually have no fun
Just to survive is the main rule of thumb.
Male spiders get eaten unless they are clever,
Lots do it once, most bees do it never.

Birds orgasm in the blink of an eye,
Antechinus do it then crawl off to die.
But Bonobos do it with whomever they can,
Then they do it again and again!
Sex seems to be fun for so many primates
Especially bonobos and us hairless apes.

But sex is dangerous, you get dead a lot.
So why didn’t life just say, “I’d rather not.”
Sex in all its forms has evolved
To help us fight off the common cold!
Well, really to fight off the more deadly types
Of viruses, bacteria and even parasites.

We shuffle the deck when we combine our gametes
It’s infections by germs which sex evolved to defeat!
Sure, we love sex now, we think its great!
But it started to let us recombinate
If there were no germs there would be no sexuality-
A whole lot of fun just to avoid a great calamity!

Now, whilst drawing morals straight from evolution
Is really pretty dumb
So is quoting Genesis
Like some God given rule of thumb.
Like… some say God made Adam and Eve, not Adam and Steve,
Now we know that’s just rubbish
First all sex was same sex and didn’t life flourish!

Often at a wedding you will hear that God gave marriage
I tend to think it’s just a bit of Genesis inspired baggage.
Evolution tells us that it certainly took a while.
And its not like western monogamy is the only human style.
Sure, marriage is great for a stable society.
The very thing Jesus threatened- he died a man of notoriety.

Yet my wife and I subscribe to it, using contraception
(well most of the time, there’s been two conceptions)
A lovely little boy, and another just arrived. 
The planet’s overcrowded yet we’re still glad he survived.
Other friends have no kids, though they have often tried.
It doesn’t help when people say it’s for God to decide!
Babies come when a sperm makes it to an egg
Not when God decides it- we do not have to beg.

Now, sex to get our kids was a highlight bar none,
But we’re not having any others, and sex is still fun.
At least I hope it will be after I get the snip.
Lucky I’m not catholic but a protestint!

These days Christians say sex is great-
For a married woman and a man.
The problem is that most then say
That nobody else can.

But any ethic which ignores the fact that we’ve evolved
Is an ethic that will leave many problems still unsolved.
I cannot give you all the answers in a silly little poem
Or if I did it would not rhyme and I can’t stand that.

But by now it should be obvious to any sensibilities
That heterosexual marriage does not exhaust all possibilities!
While I can’t vouch for bloke to bloke, about it many rave,
And when there’s only women- for many friends that is the fave.

Enough already! 
You either get the point, or you stopped reading long ago.
If you haven’t started having sex you should prolly take it slow.
Sex should be a lot of fun
But it isn’t always so!

Sex is spiritual, mystical, emotional, relational
Luminous, numinous, even educational

If you’re having sex I hope you’re having fun
Even if it started to avoid those pathojuns!

Now the poem’s over and because I am a priest
I’ll leave you with this little thought which might be a start at least.

•         The future church calls people to love of God neighbour and self; to relationships which express a righteousness…
•         modelled on Jesus the Christ, informed by evolutionary biology, and appropriate to our current ecological context.
•         freed from a simplistic application of Genesis, with its static view of creation

It’s from a talk I gave last year, the internet it’s on:
Google christian sex evolution then add Jason John