On Earth, sex is essential for many lifeforms to survive - but elsewhere in the universe it might not even exist.

In an exclusive interview with MailOnline, Richard Dawkins explained how the need for us to have sex is one of the great unanswered questions of evolution.

He added the need for two genders to reproduce is 'problematic' and finding alien life could be key to discovering why we have male and females, instead of a range of genders.

While Richard Dawkins (pictured) believes aliens and humans share certain traits, there are others that will fall by the wayside - including sex. He told MailOnline that sex is a great unanswered question of evolution, and finding alien life could help solve the mystery of why most animals rely on it to reproduce

Mr Dawkins made the comments to MailOnline at the the Starmus festival in Tenerife, an event that features talks from leading experts in space, science and astronomy.

'Does there have to be sex in an alien world? I think probably not,' Mr Dawkins explained. 'It's not at all clear what sex is doing anyway. It's problematic enough.

'I wouldn't put my shirt on there being sex [in an alien world]. If there is sex, why just two sexes? Why not three or four?'

He continued: 'One outstandingly unanswered question [about evolution] is what's sex for?'

Sex would be unlikely to be 'common between different life forms,' but discovering alien life could 'teach us about evolutionary principles,' he added.

ARE WE ALONE IN THE UNIVERSE? Dawkins told MailOnline he wants biologists to start to consider what other life might be like in the the likely event we discover we are not alone. 'The number of stars in current estimates is 10 to the power of 22, and it looks as though most of them have planets, so it's feasible to say the number of planets is in excess of 10 to the power of 22,' he said. 'It would seem to be rash to predict we're the only life form in the entire universe. 'On the other hand if there was only one planet that has life then it has to be this one, because here we are. 'The alternative is to say yes, we are alone. If you want to believe that then the origin of life on this planet has to be a quite staggeringly improbable event.' 'So we're left with the rather paradoxical result that people who are trying to work out how life originated on this planet are totally wasting their time, because the theory we're seeking is not a plausible theory, it's an exceedingly implausible theory.' Dawkins explained that if there is a plausible theory for the origin of life - one that has yet to be put forward - then there's going to be 'lots and lots' of life in the universe. 'I think there's lots of life in the universe, but that's just a hunch. It may still be very rare; it may be so rare that there are only a billion of them. 'If there are only a billion life forms then they will probably be so spaced out from each other that they'll never know each other and never come in contact. 'If they do come in contact, if we ever come in contact, it will almost certainly be by radio than by actually bodily meeting. Advertisement

And he believes that 'the fact we do see sex so ubiquitously [on Earth] is very telling.

'We do see no sex as well, asexuality does happen, so it's not absolutely essential.

'If you look at the distribution in the taxonomic tree of life, what you see is that asexual reproduction seems to crop up.

'With one exception, there is no major branch of animal - clade - all members of which produce asexually.

'The fact that it's sporadic, that it crops up here, here and here but not in major clades, suggests that when it does crop up it may flourish for a short while of evolution, but then it goes extinct.

'That could be a very telling fact.'

In Dawkins' talk at the Starmus festival yesterday he spoke on alien taxonomy, and what we might expect aliens to look like.

Dawkins pondered whether the way certain animals have evolved on Earth has been random, or followed a path that would be similar for any alien life forms.

In particular, he discussed how organs such as eyes, on a world where light was abundant, would be very likely to evolve in a similar way.

And even things such as religion, as society develops, would be shared by humans and an intelligent extraterrestrial race.

On whether aliens might have their own religions Dawkins said: 'I think it wouldn't be totally unsurprising.

After all, he said, religion has arisen in every single civilisation that anthropologists have ever looked at that.

'I suppose it's plausible that any alien life form which is on the way to developing the sort of technology that's capable of reaching us would be likely to go through a preliminary phase of uncertain groping in the dark,' he added.

'Before they hit upon truths like Newton's laws, which are universal, and Einstein's theory of gravitation, which is also universal, they might well go through a phase of groping in the dark.

'It's something we might recognise as religion.'

Dawkins said he wants biologists to start to consider what other life might be like in the event we discover we are not alone - which he claims is increasingly unlikely.

Mr Dawkins (pictured) also said he wants biologists to start to consider what other life might be like in the event we discover we are not alone - which he claims is increasingly unlikely. He believes there's lots of life in the universe, and its may be so rare and spaced out, it will never come into contact

The number of stars in current estimates is 10 to the power of 22, and it looks as though most of them have planets, so it's feasible to say the number of planets is in excess of 10 to the power of 22, said Dawkins.

He said It would seem to be rash to predict we're the only life form in the entire universe.

'On the other hand if there was only one planet that has life then it has to be this one, because here we are,' he said.

'The alternative is to say yes, we are alone. If you want to believe that then the origin of life on this planet has to be a quite staggeringly improbable event.'

WHAT IS THE STARMUS FESTIVAL? The Starmus festival is an event held in Tenerife that features various talks from leading experts in space, science and astronomy. It hosts presentations from astronauts, cosmonauts, Nobel Prize winners and prominent figures from science, culture, the arts and music. Guests include Stephen Hawking, Richard Dawkins, Brian May, and Alexei Leonov - the first man to perform a spacewalk. 'The most important thing for me is to see people leaving Tenerife satisfied and inspired,' said astrophysicist Garik Israelian, who runs the event. This year's event, hosted at the Ritz-Carlton Abama hotel, runs from 22 to 27 September. Advertisement

'So we're left with the rather paradoxical result that people who are trying to work out how life originated on this planet are totally wasting their time, because the theory we're seeking is not a plausible theory, it's an exceedingly implausible theory.'

Dawkins explained that if there is a plausible theory for the origin of life - one that has yet to be put forward - then there's going to be 'lots and lots' of life in the universe.

'I'm just pointing out a kind of incompatibility between the belief that we're unique, which many want to believe, and hunting for the origin of life on this planet, which is a lost cause if you want to believe that,' he continued.

'I think there's lots of life in the universe, but that's just a hunch. It may still be very rare; it may be so rare that there are only a billion of them.

Dawkins said if there are only a billion life forms then they will probably be so spaced out from each other that they'll never know each other and never come in contact.

He believes if they do come in contact, it will almost certainly be by radio than by actually bodily meeting.

'That's because radio waves get propagated in all directions, and so we could be being bathed in radio emissions of some extraterrestrial civilisation,' he said.

On what he expects to be found first, alien life or the origin of our life, Dawkins said: 'I would think finding a plausible theory of the origin of our life.

'If we can find a plausible theory then that pretty much means there's lots of life.'

The comments were made at the Starmus festival in Tenerife. It hosts presentations from astronauts, cosmonauts, nobel prize winners and prominent figures from science, culture, the arts and music. This year's guests include Stephen Hawking (pictured), Brian May and Alexei Leonov - the first man to spacewalk

One opinion he would like to distance himself from, though, is the possibility of life on Earth being seeded by aliens.

'I was interviewed by a creationist film and the man said "can you think of any conceivable way in which life on this planet could have been intelligently designed?"

'So I said the only conceivable way I can think of is not God, which is what [he wanted] me to say, but alien seeding. But I explicitly said I do not believe in alien seeding.

'If you really press me to think of how intelligence could ever have designed life on this planet, the only possibility would be alien seeding.

'That's very different from saying I believe in alien seeding. It's been distorted possibly maliciously by a creationist.'

If there is life out there, however, Dawkins thinks it is likely they follow similar evolutionary principles to life on Earth.

'Does life have to be Darwinian? I think it does,' he said.