This old earth has spun ’round the sun 40 times since my founding egg and sperm got cozy with each other, and yet I’m still a solo act: no wife, no family, no tribe. While a life partner and tribe can be left to happen whenever they happen — if they happen — I’m at the point where I think I need to either become a daddy, soon, or give up the idea once and for all.

Hope floats.

Photo: iStockphoto.

If I ever did co-create a baby, I would want to revel in being a father, rolling and tumbling and running and wrestling and shouting and dancing. I wouldn’t want to be dragging along, worn out and gasping for breath — and I can’t assume I’ll be spry enough to match a 10-year-old at 55.

But here’s the rub: I’m also striving to progressively reduce my destructive impact on the world, walking a path to reach sustainability. Yet I live in a world of almost 6.5 billion people, up from 3.3 billion when I was born and projected to be a smidge over 9 billion when I’m 80 (oh, you cockeyed optimist, you!). I can’t imagine how anyone looking at numbers like those could conceive with no qualms. Growth — in both population and consumption — is tearing the web of life apart, and I’m convinced we need to not only stop growing but start scaling back. Given that, how in heck could I possibly justify having a baby?

It’s true that, if the average number of surviving children born per woman worldwide from now on was only one, the population would begin to slowly decline in the foreseeable future. In that imaginary world, it might be pretty easy to convince me that it was OK to have one myself. But even though the global fertility rate has been declining over the last few decades, it’s still an average of 2.6 children per woman, according to the most recent U.S. Census Bureau estimates — so no help there.

Of course, it’s not merely a question of weighing the direct eco-impact of bringing a child into the world, either; there’s also the issue of priorities. I am a writer and community activist, and my mission takes a great deal of time and energy. So do children. If I chose to both be a writer/activist and have a child, one or the other would receive less of me than I want to give, by default. With so much to be done in these days of pervasive pollution, runaway deforestation, climate disruption, extinction, and so on, can I afford to split my life between my mission and nurturing a child?

From another perspective, it’s a mighty odd thing for someone to consciously choose not to reproduce. I’m pretty sure that counts as what biologists might call an evolutionarily unstable strategy, or a behavior that tends to be eliminated from the gene pool through evolutionary selection. Those who have no reproductive drive are obviously not going to pass on that tendency — or any other, for that matter. So why am I even thinking about this? What makes me an evolutionary exception?

As I understand it, things are pretty simple among other mammal species. When ecological conditions deteriorate beyond a certain stress point, the females don’t cycle into their fertile phases, and they resume doing so only when conditions improve. No muss, no fuss, no difficult decisions to make. Human females sometimes experience a similar biological effect — it happens to athletes who are training hard and eating restrictive, calorie-deficient diets — but most of us in the industrialized world aren’t anywhere near that active, and the eco-stresses we face don’t generally take the form of food scarcity. I’m not going to be relieved from making a decision that way.

Taking all this into consideration, what’s a guy to do if he’d love to be a daddy but also loves the world? He can only make the best choice he’s able to see, given the knowledge he has, relying as best he can on his gut feelings, and driven by the values he holds dear.

In my case, that means I’ve decided to drown myself in the gene pool, never to make a baby of my own.

I’ll do my best to help my loved ones raise the children they choose to have, and I won’t hold their choices against them. I certainly don’t expect or want everyone to make the same decision I’ve made, and I can well understand why some won’t. Maybe I’ll choose to adopt someday, which would give me the chance to raise a child to love the world as I do without adding to the population.

But still, I’ll never be able to look into my daughter’s face and see echoes of her mother, my mother, my father — myself. I resent being born into a culture that’s so destructive to the living community that I can see no better alternative, and I’m angry at all those who came before me and let it get to this point.

And I’m not going to pretend that forgoing daddyhood doesn’t leave a ragged gash in my heart, because it damn sure does.