What is your purpose in life? You might say: to make the world better, to cure cancer, to pester my little brother, to write a novel. But, biologically, is your purpose really just to have lots of little versions of yourself? If so, what does that really mean for what we do each day, our culture and our society?

At Scientific American, Lawrence Rifkin attempts to answer this question. First, there’s the familiar argument for babymaking as a life goal. Evolution says that you want your genes to live on forever. The best way to do that is to bestow those genes on as many tiny replicas of you as it is humanly possible to create. (It’s even possible for one woman to produce 69 children, apparently.)

Of course, living solely based on baby-making can have its downsides, as Rifkin writes:

Fundamentally, as humans, the problem with identifying the meaning of life with having children is this — to link meaningfulness only with child production seems an affront to human dignity, individual differences, and personal choice. Millions of homosexuals throughout the world do not have children biologically. Millions of heterosexual adults are unable to have children biologically. For many adults, not having children is the right choice, for themselves, the world, the economy, or for their would-be children. Socrates, Julius Caesar, Leonardo da Vinci, George Washington, Jane Austen, Florence Nightingale, John Keats, Vincent van Gogh, Vladimir Lenin, and Steven Pinker as far as we know did not have biological children. Would we deny the meaningfulness of their impact or existence? The meaning of life for childless adults — roughly 20% of the population in the U.S. and U.K. – has nothing to do with fame, but everything to do with what makes life meaningful for everyone: experiencing pleasure, personal relationships, and engagement in positive activities and accomplishments.

And interpreting the principle of evolution simply as “make loads of kiddos” isn’t really right either. Rifkin argues that it’s not simply about how many babies you make, but how fit they are for their environment. And there are all sorts of things that evolution deals with that extend beyond the individual. Rifkin writes:

Evolution by natural selection occurs by differential survival and reproduction of genes in a population as a consequence of interactions with the environment. There is also the danger of overpopulation, which could result in famine, disease, and environmental catastrophe, perhaps jeopardizing the future evolutionary success of the entire species. So, ironically, perhaps not having children is the best way to ensure longevity of the human genome. Unlike other animals, we can be conscious stewards of the future.

So, Rifkin concludes, in some ways your purpose on this planet is indeed to make babies. But that doesn’t necessarily mean to make your own babies. People who adopt could be helping the species as a whole. Those who don’t have children might play their part, too. His final conclusion is that while we think our individual actions are the most important, they’re really not. “We perform our solos with passion, but we are playing in nature’s grand symphony,” he writes.

More from Smithsonian.com:

Movie of the Inside of a Woman’s Body as She Gives Birth

Robot Babies