I still beat myself up about how much of an idiot I was over so many years. I’d always seen having children as a key part of my purpose on this planet, believing that creating new life was part of my biological destiny. It was fundamental to how I navigated the world.

I’m slightly jealous, in truth, of those who don’t have that imperative. My wife Anya, for instance, just enjoys life as it comes.

It was August and she and I were on an idyllic holiday in Denmark. My brother came to see us, keen to deliver some news. We walked down to the end of the garden and, looking out across the Baltic Sea, he told me his partner was pregnant.

It’s astonishing how quickly my brain went into overload. Even as my arms raised up to hug my younger brother, I was thinking: oh shit. Not at this joyful information – for him I couldn’t have been happier. Rather, I was immediately asking myself: how has he got round to this before me? Christ, I thought, Anya and I are both nearly 40. What on earth had we been waiting for? Anya’s clock was ticking. My clock was ticking. I’d failed to recognise my needs, and somehow forgotten about the passage of time.

I’d always assumed we’d have a large litter, but in an instant I realised the prospect of that was all but gone. Of course, I’d wanted to keep up my adventures and was nervous about the responsibilities that would come with fatherhood. But having children had always been a priority. My wife and I had long had the opportunity. But for some reason we hadn’t taken it.

As I pulled my brother close, all this came crashing down. I’m so pleased they got pregnant when they did or I might not have considered it until retirement. I talked to Anya, and we agreed to start trying. She’d be pregnant in no time, I thought, and, filled with excitement, we cracked on protection-less that very night.

A few months in, we’d made no progress. It was strange given we were old enough, I thought, to know what went where. Resolutely, we entered the world of fertility consultants – tube and egg checks, and testing sperm. The process was pretty shit, quite frankly. Certainly a ball-ache. What was surreal, is that by nature I’m a pessimist. My glass is only ever half full. Yet I entered this with total confidence, convinced the tests would all go well. Once completed, we sat down for the results.

“I won’t make any bones about it,” the specialist informed us, “you are basically infertile.” Conceiving, she said, would be impossible. We had no chance of having children. It was the starkest of messages and I could hardly take it in.

I had loads of sperm, she explained, but their morphology was terrible, the shape and structure deformed. I had 0% normal sperm. Nothing. Their mobility was no better – they uselessly swam around in circles without an egg-breaking hope.

I’m a mission-oriented, goal-focussed person. Often the projects I work on are complex and overwhelming and it’s my job to make sure problems are overcome. As I listened to her prognosis I felt powerless, our future slipping out of my hands. Receiving this information, I was totally unequipped.

It was a long walk back, in every sense, to our flat in north London. I was in a daze, as if I’d been drugged. I was so disconnected I couldn’t mentally associate myself with my failure of a body. The sunny park looked like a film set with tons of people pushing prams. You never notice them more than when you’re desperately trying for a child. I didn’t speak to anyone about how I was feeling. I don’t think it was shame or embarrassment, I just didn’t recognise the importance of talking at the time. I started to drink too much.

Lovingly, Anya dragged me back to my senses. Together, we started to process the news. We’d try alternative techniques, get a second opinion. We looked online, but found little obviously reliable information. It felt like entering the Wild West, a place where medical research hasn’t quite caught up. Conception is a fundamental, primal act, but the science around it is still so uncertain. There’s so much guesswork, unproven theories and chance. It’s like a fertility casino, and we rolled the dice.

Some “experts” we visited had ridiculous suggestions: have sex every day; every three days; do it upside down. When you’re desperate you’ll try anything. It felt like an industry trying to muddle its way through a healthcare crisis, as its patients are too.

Reading more about the subject saw my frustration turn to anger – fertility is on a downward spiral and we’re being poisoned by the modern world. Some experts believe the sperm counts of western men have fallen by more than 50% over recent decades and that their defectiveness is on the rise. Meanwhile, others believe the number of miscarriages is increasing and that egg quality is in steep decline.

One of the most significant problems affecting fertility is endocrine-disrupting chemicals (EDCs), which can mimic and interfere with the hormones that regulate and run our bodies. EDCs are used in plastic and thousands of products, including cosmetics, toys, clothes, soft furnishings, pesticides and the linings of tinned foods. They’re everywhere. Usually they’re not even listed on labels. Yet for decades study after study has shown they pose an existential risk.

We’re poisoning ourselves out of existence, and our consumer capitalist democracies seem incapable of stopping it. It’s a reality of our health and wellbeing that should fill us with rage and fear.

In time, I came to terms with our situation. I thought a lot about the horror I’d seen in all my travels. Yes, this was traumatic, but I’d witnessed unimaginable suffering in others. Once I arrived at acceptance, I started to transform parts of my life. Many experts had told us that with dedication our prospects might not be quite so bleak.

I went on a health kick, cutting out some of the things I’d always felt made life worth living. Gradually, we saw my sperm’s scores improve. The transformation in my sperm’s morphology once I lived a healthier, cleaner lifestyle convinced me there needs to be intervention to stop us poisoning ourselves out of existence.

Mother Nature took pity on me, helping me see off the chemicals I’d spent a lifetime consuming. In less than a year, enough of my boys became healthy enough to have a shot. It was time, we were told, to try IVF. For Anya, this would mean enduring invasive treatment. My job would be short and simple. I tried to remain considerate of that fact.

Because Anya and I had conflicting priorities, I suggested we used a 0-10 point system that I often use to help quantify mine and others’ beliefs and desires. Say we’re filming in South America and have 60 seconds to decide whether to join a drugs raid with local police: I ask everyone to make a snap judgment for how positive they feel about proceeding. Whether out on location, or sat in the living room, I use the same method. The higher you score a statement, the more you agree. We played the game. She was enthusiastic, but I needed children more than her. I recognised the physical suffering of both IVF and a potential pregnancy (and the rest of it) for her. In return, she recognised fatherhood was a necessity for me. We decided to give it a shot.

On a crisp, sunny afternoon in early spring 2011, we walked out of the Royal Free in London, holding our newborn baby. For a moment I’d felt like security would stop me. We didn’t have a certificate, we’d not been trained. Stepping out into the real world felt an elemental moment. It was a total and utter delight. After all we’d been through, I’d presumed this moment would never come. I tried to keep a sense of perspective – refraining from announcing our offspring to every stranger on the street.

Nine months earlier, we’d been incredibly lucky when our first round of IVF had succeeded. For weeks, we’d assumed it hadn’t: Anya wasn’t tired, tender or nauseous. Hope had slipped away. But then, somehow, one spartan embryo had prevailed.

Now I’ve written a book, Journeys to Impossible Places, in which I recount my trips to many corners of the world – and it would have been dishonest not to include my journey to fatherhood, too.

Having a conversation with my son – now 10 years old – about what to include was scary. He has strong opinions. I was worried something I’d written would upset or embarrass him. Thankfully, he was up for sharing. I found talking to him cathartic, too.

Reflecting on what the experience taught me, I’ve certainly become more determined to regularly assess what I want, whether from life or specific situations. If I decide pursuing something is important, I try to act urgently and aggressively – full throttle – rather than be half-arsed. I know I might not make it, but I give those desires everything I’ve got.

Mostly, I’ve been instilled with a sense of urgency. It’s so easy to be seduced into thinking we’re timeless and eternal, with all the time in the world. Time ticks by fast. My priorities had always been family and travel, and I presumed we’d have forever. Suddenly you’re middle-aged and the end of the pier is in sight.

Looking back at the experiences and adventures I’ve had, there’s been beauty and danger, thrills and the unknown. To say that the most normal, natural act of having a kid is the hardest, most moving and exhilarating button-tweaking journey I’ve taken is quite something. I can’t believe I put it off for so long, I feel like such a fool.

Journeys to Impossible Places by Simon Reeve (Hodder, £20) is available from guardianbookshop.com for £17.40. The Lakes with Simon Reeve airs Sundays at 9pm from 14 November on BBC Two