During my first pregnancy, my mother often reassured me that I had nine months on my side.

Facing my due date, the stresses that occupied me were practical: What did I need to receive a baby into our life and home, and when would we be able to purchase, assemble, and study it all?

Her point was simple: you’ll figure it out, you have plenty of time.

I spent commutes game-planning feeding and sleeping schedules, bedtimes reading about how to care for a child during the first year of life. Every aspect of a newborn seemed like a mystery that could be solved by opening a book.

It all seems so quaint now. The challenges of parenting are so profound that it is impossible to appreciate them without actually becoming a parent.

Before becoming pregnant, it is natural to assume that pregnancy is like biological math, an equation that necessarily yields the expected result. Then, some of us learn that it doesn’t always add up.

Assuming a successful pregnancy, it becomes natural to assume that the baby will be healthy. Then, some of us learn that being pregnant involves lots of testing, and that the tests don’t always report good news. We learn that parenting is so difficult that even producing a baby who thrives is itself miraculous.

And then we learn about a new brand of hero: the parent of a baby who is, or grows into, a child with an illness or disability. We learn to be grateful that our child can breathe on her own, that he can learn to walk, that she proves able to talk. We remind ourselves, however silently or belatedly, that, really, if our child has its health, we have everything.

Yet even as a parent of a healthy child, parenting remains daunting. The effort does not lie, however, in the concrete, tangible aspects of parenting – the feeding and the changing and the bathing and the driving and the scheduling and the godforsaken birthday parties – although those are exhausting. The real effort lies in the job of teaching a blank slate how to become a good person.

Mastery of life is not a precondition to becoming a parent. We assume the responsibility of teaching someone else how to do what we have not yet figured out. We teach, even as we learn through and with our children.

I have a short temper; how do I teach my son how to moderate his emotions? I am inclined towards shyness in social settings; how do I teach my daughter a quiet confidence? I often worry about how people perceive me; how do I teach my children that being themselves is more than sufficient?

The nuances of behavior are magnified during parenting. Children should cooperate, but not if someone is asking them to do something that is wrong. Children should have fun, but they need to learn responsibility. Children should be independent thinkers, but they must respect authority.

For every rule, there are exceptions, and children need to understand them all.

It is OK to slap someone’s hand in greeting, but never slap someone’s cheek. It is OK to hug someone, but never too hard. It is OK to talk, but never interrupt.

You wake up one morning and your child no longer wants to go to school because her old friend is treating her like a new enemy. What do you say? You know what your child is afraid of. Do you make her test those fears in the hope she’ll get over them? You see that your child is not interested in learning skills you know are required. When do you start pushing him?

She asks you a question that makes you wonder, too. How do you answer?

Parenting asks you to assert authority on a subject with few experts. It dares you to predict outcomes that are unknowable. It forces you into a science experiment where the stakes are the child who, once upon a time, you worried over when she hiccuped.

Parenting teaches you that, if you don’t feel utterly humbled by it, you’re probably doing it wrong.

Abby Diaz grew up in Falmouth and lives there again, because that’s how life works. She blogs at whatsleftover.com. Follow Abby on Twitter: @AbbyDiaz1.