Unlike your average scientist, Craig Venter is an alpha male. He gets things done, he makes money and he does things in boats that make betas like myself hyperventilate. Why does a yacht make him want to risk his life?

“Rarely have I ever felt . . . maybe that one storm in Bermuda in the small boat . . . The simple thing that saved me in that storm was dragging the warps behind the boat. It probably kept me from being flipped over in the waves.”

Venter was riding the waves again last week. He is close to making an artificial life form, very much an alpha male thing. It will, says Venter, conquer infection. Is he playing God?

No, he’s more Adam, a new human beginning. He is, as he puts it, “the first chemical machine to gaze upon his own sequence”. He knows, in other words, his own DNA. He was the first man to decode the human genome, the announcement of which in 2000 was hyped as one of the great moments in history, like Galileo, Newton and Darwin rolled into one, but bigger.

Then, weirdly, nothing seemed to happen: “The hype is correct if you’re talking about a timespan over the next century. It certainly was not correct and was frighteningly misleading to people if they were thinking in terms of months or years.”

The hype was, as ever, politics. Venter had been working on the genome for the US government, but he grew restless with the bureaucracy. So he left and did it privately. Government scientists on both sides of the Atlantic hated him for it. They said he was privatising our genes and feared that, if he could do it for $300m, that meant they would not get the taxpayers’ billions they had been promised.

“I think, certainly in the US, they were worried because there was now another group doing it that didn’t cost the government any money, that the government would slash their funds. So I think they kept hyping it as part of the justification to the US Congress to keep spending billions of dollars.”

In the end the public and private sides announced the genome jointly, flanking a beaming Bill Clinton with Tony Blair on a screen. Venter, being alpha, got Blair’s speech changed. He said he wouldn’t turn up if Blair delivered his hymn of praise to the public sector.

Now Venter has moved on. He was sacked by Celera, his sequencing company, because his business plan was not what the suits wanted. He wanted to release the genome and charge people for access to the database. It made money but not enough. So now he’s creating artificial life and saving the planet.

First, who is he? The best answer so far is his new autobiography, A Life Decoded. It took him, he says, five years: “I started thinking about this quite a while ago, in part because of my unusual background and route to being a scientist, ending up in the military first and then Vietnam. Then the whole issue with the human genome and having at least half a dozen books out there of other people interpreting my stuff. So I thought it might be a good chance to try and put all of this in perspective.”

Brought up in San Francisco, he was a bad boy who did little at school: “I think it’s due in part to how my brain functions. I’m extremely good at concepts and complex integrated information. I’m pretty bad at memorisation and our education system is based on memorisation.”

Somehow he caught up, discovering his vocation as a navy medic in Vietnam: “All of a sudden I was responsible for people’s lives in the middle of a war.” He saw one man struggle with his injuries and live and another despair of his injuries and die: “Obviously our spirit and how we approach things mentally has a huge impact.” Life, he saw, was the issue. He went home and decided to learn all about it.

Pretty rapidly he was a biochemist, physiologist and pharmacologist; in 1984 he joined the National Institutes of Health in Washington, the biggest medical research institute in the world. The rest, as they say, is history.

What is striking about the book, and indeed the life, is a tension between hard genetic determinism – the belief that our DNA is actually what we are – and a more complex vision of the human self: “The term I’ve been using in my recent lectures after publication of my genome is that we are definitely genetic animals. But there’s a fine line in my mind between having genetic influence on personality, on behaviour, on every aspect of our lives, and having those be deterministic. I’ve never talked to a parent who didn’t realise the moment their child was born that they had a unique personality. I think that’s part of that genetic wiring that we get, but you as a parent, I’m sure, have had a great influence on the scope and direction of that personality.”

These are deep waters. Nothing we have yet discovered begins to resolve the nature-nurture debate except in a few very simple cases – if you have the gene for Huntington’s you’ll get Huntington’s, irrespective of nurture. What we don’t know is which, if either, is the main player in the conflict between our biology and the world.

The key problem is that far from being the simple computer code we once thought it was, DNA is fabulously complex. When I last interviewed Venter a decade ago, he said our DNA was too complex to be designed by man and probably even too complex for natural selection. The problem has worsened: “With the publication now of the full genome, it’s clearly more complicated than ever.

“All our data from the environment and other places is telling us there are different components to our personalities. Certainly step by step everything’s just a point mutation and things change. But I don’t think that can explain everything. People have this simplistic view of Darwinian evolution as random point mutations in the genetic code followed by natural selection. No, I don’t think that would have got us out of our genome.”

Venter is 61 and still out there on the dangerous edge of things. He is close to creating an artificial life form, having made an artificial chromosome. This, he says, would be “a chassis on which you could build almost anything”. Clearly “anything” includes new medical treatments and deliberately or accidentally created malevolent new bugs. Like I said, this is the dangerous edge.

He is also working on a bio-engineered green jet fuel. We may soon be able to take carbon dioxide emitted by vehicles or power generation and turn it back into fuel. In addition he has been using his yacht to research the oceans. He has found a hitherto unimagined range of genetic diversity down there. And he has started a programme to crack the nature-nurture issue. This involves assembling 10,000 human genomes over the next decade. These could then be correlated with psychology and life outcomes.

At 61 he is weighing his life chances against the conflicting messages from his DNA. He has both strong heart disease and strong longevity indicators: “So, who wins out – my longevity genes or my cardiovascular genes? And there’s interprinting and other things on top of it, even what we’re reading in genetic code can’t tell us. I’m struggling for a better analogy than blind men all describing and holding to one bit of it.”

Venter, the second Adam, the alpha male, is sailing, as ever, blindly into the unknown.

A Life Decoded by Craig Venter (Allen Lane, £25.00)

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