My life is full of adventure – but being a father has been the most rewarding journey of all

I still feel ashamed about the idiot I was for so many years. I had always viewed having children as a crucial part of my purpose on the planet. I believed that creating new life was my biological destiny. It was integral to my ability to navigate the world.
I am a little jealous of people who don't have this imperative. For example, my wife Anya just takes life as it comes.

August was here and she and my brother were on a relaxing holiday in Denmark. My brother, eager to share some news, came to visit us. He walked me down to the end and told me that his partner was pregnant.

My brain went into overload so quickly it was amazing. My arms extended to hug my younger brother and I thought: Oh shit. He was so happy that I could not have been happier. Instead, I immediately wondered: How did he get to this? Christ, I thought, Anya, and I, are both almost 40. What the hell had we been waiting? Anya's clock was ticking. My clock was ticking. I had lost track of the time and failed to recognize my needs.

Although I had assumed that we would have a lot of litter, I realized in an instant that the possibility of having a large litter was almost gone. While I wanted to continue my adventures, I was also anxious about the new responsibilities of fatherhood. But, having children was always a priority. It had been a long time since my wife and I had this opportunity. We didn't take it for some reason.

All this collapsed as I pulled my brother closer. It's so great that they got pregnant. I wouldn't have thought of it until after retirement. Anya and I spoke, and we decided to try. I was certain she would be pregnant within a few days. We were so excited, that we decided to go protection-less the next night.

We had not made any progress after a few months. This was odd considering we were old enough to know where things went. We resolutely entered the world fertility consultants tube, egg checks, and testing for sperm. It was quite a miserable experience. It was certainly a pain in the rear. Surreal was the fact that I am a pessimist by nature. My glass is never half-full. I was confident that the tests would go well, so I went into this test with complete confidence. After the tests were completed, we sat down to receive the results.

The specialist told us that you were basically infertile. There was no way we could have children. It was one of the most stark messages I had ever heard and it was hard for me to take in.

She explained that I had a lot of sperm but that their morphology was horrible, and that the structure and shape were deformed. I had 0% normal Sperm. Nothing. They were unable to move and swam in circles, wasting their time without any hope of achieving egg-breaking success.

It was told us that we were not likely to have children.

I am a goal-oriented and mission-oriented person. Many of the projects that I work on are complicated and overwhelming. It is my job to ensure that problems are solved. I felt helpless as I listened and watched her future predictions. This information left me completely unprepared.

It was a long, difficult walk to return to our flat in north London. I felt like I had been taken to a drug, and I was completely lost. I could not mentally connect with my body's failure. It looked like a movie set, with hundreds of pram-pushers. They are more noticeable when you're desperately trying to have a child. I never spoke to anyone about my feelings. It wasn't shame or embarrassment. I didn't realize the importance of speaking at the time. I began to drink excessively.

Anya loved me and brought me back to my senses. We began to process the news together. We would try other techniques and get a second opinion. We searched online but could not find any reliable information. It was like being in the Wild West, where medical research is still far behind. Although conception is an essential, primordial act, the science surrounding it is still very uncertain. It's a lot of guesswork, unproven theories, and chance. It's almost like a fertility casino where we roll the dice.

We were given some bizarre suggestions by experts: Have sex every day, every three days, upside-down. You will do anything if you are desperate. It was like the industry was trying to navigate a healthcare crisis.

I became angry when I read more about the topic. Fertility is in a downwards spiral and we are being poisoned daily by the modern world. Experts believe that the number of western male sperm has dropped by more than half in recent decades. This is a sign that the quality of their eggs is declining. Others believe that miscarriages are increasing and eggs quality is declining.

Endocrine-disrupting chemical (EDCs) are one of the biggest problems that can affect fertility. They mimic and interfer with hormones that regulate and control our bodies. EDCs can be found in plastics, as well as thousands of other products such cosmetics, clothing, textiles, pesticides, and the linings for tinned food containers. They are everywhere. They are often not listed on labels. They pose a risk to your health, and have been for decades.

Our consumer capitalist democracies are incapable of stopping us from poisoning our existence. This is a fact of our health and well-being that should make us rage and fear.

I eventually came to terms my situation. I was horrified by the things I had seen on my travels. This was traumatizing, but it also brought me to the realization that I had witnessed other people suffering. After accepting my situation, I began to change parts of my own life. Experts had warned us that our prospects may not be so grim if we work hard.

I have learned a lot from this experience and am now more determined.

I embarked on a health-related kick to get rid of some things that I didn't believe made my life worthwhile. Gradually my sperm scores improved. After I had a cleaner, healthier lifestyle, the changes in my sperms' morphology convinced me that intervention was needed to prevent us from poisoning our own existence.

Mother Nature was kind enough to help me get rid of the chemicals I'd been consuming for a lifetime. My boys were healthy enough to get a shot in less than one year. We were advised to consider IVF. This would require Anya to endure invasive treatment. My job would be simple and short. That fact was something I tried to be mindful of.

Anya and my priorities were conflicting so I suggested that we use a 0-10 point system. This is something I frequently use to quantify my beliefs and desires and those of others. Imagine that you are filming in South America, and you have 60 seconds to decide if you want to take part in a drug raid with the local police. I ask everyone to give a quick judgment on how optimistic they feel about moving forward. The same approach applies whether I am on location or sitting in my living room. You agree more if you score higher on a statement. The game was played together. Although she was enthusiastic, I needed children more than she. I understood the physical pain of IVF and the possibility of a pregnancy (and all the rest) for her. She also recognized that fatherhood was something she needed. We agreed to try it.

We walked out of London's Royal Free with our baby, on a sunny, crisp spring afternoon. It felt for a moment like security was going to stop me. We didn't have a certificate and we hadn't been trained. It was an essential moment to step out into the real world. It was an absolute joy. After all that we had been through, I thought this day would never come. I tried to maintain a sense of perspective and not announce our offspring to anyone on the street.

We had been extremely lucky nine months before our first round IVF was successful. We had assumed it didn't happen for weeks. Anya was not tired, tender, or nauseated. All hope had vanished. One spartan embryo prevailed.

Now, I have written Journeys to Impossible Places. It is a memoir in which I tell of my travels around the globe. I also include my journey to fatherhood.

It was frightening to have a conversation about what to include with my 10 year old son. He is very opinionated. I was afraid that something I had written might upset him or embarrass me. He was open to sharing his thoughts. Talking to him was also cathartic for me.

Looking back at what this experience taught me, it's clear that I have become more determined to constantly assess what I want in life and in particular situations. When I make a decision to pursue something, I will act quickly and aggressively with full throttle. I don't like being half-hearted. Although I may not be able to achieve my goals, I try to give everything I have to those dreams.

Most of all, I was instilled with a sense urgency. It is easy to fall for the illusion that time is eternal and timeless. The clock ticks by quickly. My priorities were always family and travel. I assumed we would have that forever. You suddenly find yourself middle-aged, and the end is within sight.

When I look back on the adventures and experiences that I have had, there has been beauty and danger, thrills, and the unknown. It is amazing to say that having children is the most natural, normal and natural thing I have done. However, it is also the most difficult, moving, exhilarating, and rewarding button-tweaking adventure I've ever taken. It's hard to believe that I put it off so long. I feel like a fool.

For 17.40, Journeys to Impossible Places (Simon Reeve) can be purchased at guardianbookshop.com The Lakes with Simon Reeve will air Sundays at 9pm on BBC Two starting 14 November.